1248 Journal of Medicinal Chemistp. 1974. Vol 17, 'Vo 12 shaw, and G . M. Luke, J . M e d . Chem., 17,1248 (1974). (7) R. Schwyzer, P. Sieber, and H. Kappeler, Helu. Chim. Acta,
42,2622 (1959). (8)G . R. Fearnley, G. V . Balmforth, and E. Fearnley, Clin. S e i , 16,645 (1957). (9) J . D. Billimoria, J. Drysdale, D. C . 0. Jones, and N. F. Madagan, Lancet. 2,471 (1959). (10) W. E. Parham and E. L. Anderson, J. Amer Chem Soc , 70,
Buchanan, ri ai 4187 (1948). (11) 0. E. van Lohuizen and P . E. Verkade, Recl. Trau. C h i n . Pays-Bas, 78,460 (1959). (12) L. E. Krimen, Org. Syn., 50, l ( 1 9 7 0 ) . (13) G . T. Morgan and E. Walton, J. Chem. SOC., 902 (1936). (14) W. Pollman and G. Schramm, Biochim. Biophys. Acta, 80, 1 (1964). (15) A. R. Battersby and R. Binks, J . Chem. Soc., 4333 (1958).
Synthetic Fibrinolytic Agents. 2. Selected N-Monosubstituted Bis(tetrahydroisoquinolines) Designed to Possess Enhanced Bioavailability Ronald L . Buchanan.* Vilmars Sprancmanis, Thomas A. Jenks, R. R. Crenshaw, and George M. Luke Re.earch Diuision, Bristol Laboratorie,q, Diuision of Bristol-Myers Company, Syracuse, .Vew York 13201. Received June 7, 1974 Certain S-monosubstituted analogs ( 1 ) of the bis(tetrahydroisoquino1ine) la were specifically designed and synthesized in a n attempt to enhance the oral absorption characteristics of this class of fibrinolytic agents. A number of latentiated derivatives were prepared, wherein the N-substituents were potentially susceptible to enzymatic or hydrolytic cleavage to the parent drug l a , A selection of anionic side chains was also incorporated, and a group of miscellaneous derivatives was prepared. Many of the analogs had parenteral activity comparable to the parent drug l a in the dilute blood clot lysis assay in rats, but none possessed a useful level of oral activity.
A preceding paper' described the rationale for synthesizing monosubstituted bis(tetrahydroisoquino1ines) of general structure 1 as potential orally effective fibrinolytic agents. Two general syntheses were developed, and a series of mono-N-acyl, N-alkyl, and N-sulfonyl analogs was prepared, primarily from the mono-Boc intermediate lb. Although a number of compounds possessed comparable activity to that of the parent drug la2 upon parenteral administration to rats in the dilute blood clot lysis assay, no significant oral activity was seen. This paper reports the continuation of our work in this series, describing the synthesis of a variety of compounds of type 1 where R represents a moiety more specifically designed to enhance oral absorption. either bv latentiation of the amine function or by otherwise altering the chemical nature and lipid solubility of the molecule.
Scheme I
4a X = o - C O C K " , b. S = p NO-
Me0 I-\
2
la R = H b. R = h c
Carbamate Ester Latentiation. In searching for lipophilic amphetamine derivatives that would more readily penetrate the blood-brain barrier, Verbiscar and Abood3 discovered that nitrophenyl and o-carbomethoxyphenyl carbamate esters of cu-[14C]amphetamine rapidly enter the mouse brain where they are readily hydrolyzed to the free amine. By analogy. we hoped that similar carbamates in our series would be better absorbed from the gastrointestinal tract and then be hydrolyzed in uiuo to the parent drug la. Syntheses of the o-carbomethoxyphenyl and pnitrophenyl carbamate esters 4a,b are outlined in Scheme I. Treatment of the mono-Boc-lb with o-carbomethoxyphenyl chloroformate,3 followed by removal of the Bocprotecting group, gave 4a. Alternatively, the appropriate
3a, X = o-COOCH, b, X = p - NO,
chloroformates were condensed with derivative 2,1 and the intermediates (3) were reduced by standard methods to 4a and 4b. The glycerol carbamate tic was also prepared, based on the rationale that it might be susceptible to in uiuo hydrolysis to l a , glycerol, and COz. Treatment of l b with N,N'-carbonyldiimidazole4 gave 5a. Displacement of the
Journal of Medicinal Chemistry, 1971, Vol. 27, No. 12 1249
S y n t h e t i c Fibrinolytic A g e n t s . 2
imidazole moiety by the anion of isopropylideneglycerol5 afforded t h e protected derivative 5b, which was then converted to 50 by acid hydrolysis. Derivatives Susceptible to Enzymatic and/or Hydrolytic Side-Chain Cleavage. Eckert, et a1.,6 have recently shown t h a t mono-n-propylaminoacetylationof poorly soluble biologically active aromatic amines leads to more soluble derivatives. These compounds are then susceptible to enzymatic cleavage to the free amines by a carboxylesterase of swine liver microsomes. The potential for increased bioavailability in such a derivative of la was apparent. Chloroacetylation of l b afforded 5d, which upon cond ensation with n-propylamine and subsequent hydrolysis yielded the desired analog iif.
Scheme I1
/'
6
/ #
/
\
Yrn
temp
0.
MeO
XQM,
MeO
7
c. R, = H; R,= COOCH,CHOHCH,OH d, R, = Boc; RL= COCH,CI e, R, = Boc; R2 = COCH,NHPr f. R, = H R, = COCH,NHPr g. R, = Boc;R,= COCH,OEt h R, = H; %= COCH,OEt i, R, = H; R3= (CH,),OEt i, R, = Boc; R2=(CH2),COOEt k, R, = H; R2= (CH,),COO-Na+ I. R, = H; R, = (CH,),SO,H rn. R, = Boc, R, = (CH,),CN H n. R, = H,R? = ( C H ~! t)' ? ~
N-N R, = Boc; F&= SO,-NH(CH,), p, R,=H; R,=SO,-Na+ q. R,=Boc, RL=COCHC,H,
8
should effect Boc removal to give 7, without loss of the thioformamidine function; 7 would then be susceptible to hydrolysis to the free amine as reported8 and therefore would have the potential to release la by hydrolytic cleavage in uiuo. Unfortunately, the intermediate 6 displayed this cleavage behavior upon standing in CHZC12 solution a t room temperature, being smoothly converted to lb.HC1 and precipitating pseudothiohydantoin (8) from solution. Derivatives with Anionic Side Chains. The potency of mono-N-ethyl derivatives [l, R = Et, (CHz)zSH, ( C H ~ ) Z O C ~ upon H ~ ] parenteral administration has been described previously.1 Endeavoring to maintain this potency, and to increase oral absorption, a series of anionic groups was attached to the ethyl moiety. The S-phosphorylated derivative 10a of the thiol [I, R = (CHz)zSH] was a particularly attractive candidate, since the S-P bond of such compounds is known to be highly labile in biological systems,g hence providing the possibility of liberating the parent thiol in uiuo. The monosodium salt of 10a was synthesized by treating the p-chloroethyl derivative 91 with sodium thiophosphate,lO followed by the addition of 1 equiv of NaOH (see Scheme 111).
~
0.
Scheme 111
I
r,
R,
= H;
= C&HC,H, \ 2"
s, R1=&I;R2=N0
Artini, et al.,7 in a recent study of the analgesic and antiinflammatory activities of some 4-amino- and 4-amidobenzophenones, found that ethoxyacetylamino derivatives were efficiently metabolized to the parent amines in rats. Such a derivative (5h) of la was prepared in the usual manner from l b uia the intermediate 5g. Reduction of 5h to the ethoxyethyl derivative 5i was carried out for activity comparison, since mono-N-ethyl derivatives synthesized previously had shown high intrinsic activity.1 The possibility of isolating a labile intermediate in the removal of chloroacetyl groups on amines by thioureas prompted a study of this reaction in our series. The sequence (Scheme TI) involved treatment of 5d with thiourea to give the intermediate thioformamidine hydrochloride 6. If 6 could be isolated, anhydrous acid treatment
9
0
It
1% R = ( C H , ) w - N a +
I
OH
The corresponding carboxylate derivative 5k was obtained by Michael condensation of l b and ethyl acrylate to give 5j, followed by hydrolysis and ion-exchange chromatography, Alkylation of l b with sodium 2-bromoethanesulfonate,ll followed by acid hydrolysis, afforded the sulfonic acid analog 51. Michael condensation using acrylonitrile yielded nitrile 5m, which could be treated with alu-
1250 Journal of Medicinai Chemistry. 1974. Vol. 17. .Vo. 12
and solvent removal under reduced pressure gave a crude oil (2.87 g). Chromatography on a column of neutral alumina gave the purified intermediate 3a (1.71 g, 71.6%) a s a colorless oil upon elution with E t 2 0 + 1% E t O H . Dissolution in EtOAc-Et20 and treatment with HCl(g) gave t h e amorphous hydrochloride salt after solvent removal. Anal. (C38H46NZOs.HCl) C, H , N. T h e free amine 3a (0.71 g, 0.0011 mol) was dissolved i n 35 ml o! reagent MeOH and cooled t o 5-10", and sodium borohydride (100 mg) was added with stirring. After stirring a t room ternperature for 2 hr, H 2 0 was added, the MeOH was stripped off under reduced pressure, and the product was extracted into EtG1.4c. The usual washing and drying procedures gave the product (0.628 g. 87%) a s a light yellow gum. Column chromatography on neutral alumina gave purified 4a (201 mg) upon elution with EL20 + 1 4 % EtOH. The HCI salt was prepared in the usual m,anner The n m r spectrum (CDC13) showed two singlets for the methyl ester ( b 3.53. 3.76). Heating of t h e sample to 80" caused the peaks to coalesce to a singlet ( 6 3.67). indicating the presence of ,"(ita tional isomers at the amide linkage. Anal l C 3 ~ H . ~ ~ N z O + . IH('. Cl H , N.Mass spectrum m l e 660 (MI of' free base). Method B. T h e mono-Boc intermediate l b (1.;3g. 0.00284 m o l ) was treated with o-carhomethoxyphenyl chloroformate (0.3 i:. 0.0023 mol) as in method A, affording 1.47 g of a pale yellow o i i . The oil was then d i s d v e d in 30 ml of 97% formic acid and stirred a t room temperature for 2.5 hr. The tormic acid was stripped of! under reduced pressure and the residue was dissolved in water and extracted with E t 2 0 to remove any neutral material. Basif'ication of the aqueous phase with 5% NaOH solution and e x t r a c ~ rion of the product into EtzO afforded crude la (1.167 g~ after drying ( M g S 0 4 ) and solvent removal. Column chromatograph) on neutral alumina gave pure 4a (0.7 g, 47%) upon elution with Kt20 + 2% E t O H . The HCI salt was prepared in the usual manner and the resultant 4a.HCI {vas identical i t l v ir. and n m r ) with material from method A . 1 , l '-Heptamethylene-ti,7-dimethoxy1,2,3,4-tetrahydroiso quinoline-2'-(p-nitrophenoxycarbonyl)-~~',7'-dimethox~,3',4'-tetrahydroisoquinoline(4b) Hydrochloride. The intermediate dihydroisoquinoline 3b was prepared from 2.2HCl (5.26 g, 0.0095 mol) and p-nitrophenyl chloroformate (2.02 g, 0.01 moll hy method A , described for l a . Chromatography of the cnide product on a column of neutral alumina afforded Jb (2.9 gr upon elution with EtzO. Treatment o f 3 b ( 2 . 5 g) with sodium horohydride (1.7 g j in 5leOH (120 ml), as descrihed for 4a, afforded 2.12 g (8:3.7410)of crude product. Column chromatography on neutral alumina gave a pure fraction of 4b (1.05 g) upon elution with Et20 + 1% E t O H . Treatment with HCl(g) in the usual mannpr gave Ib.HCI. Ancd ( C ~ G H ~ ~ N ~ O C, ~ .H H, CNI. ) I , 1 '-Heptamethylene-6,7-dimethoxy-l,2,3,-1-tetrahydroisoq u i n o l i n e - 2 ' - (2,3-dihydroxy-n-propyloxycarbonyl)-~~',7'-dimethoxg- 1',2',3',1'-tetrahydroisoquinoline ( 5 c ) Hydrochloride. The mono-Boc-lb i7.0 g, 0.012 mol) and carbonyldiimidazole (1.95 g, 0.012 mol) were dissolved in 175 in1 of dry T H F and stirred at rooni temperature in an atmosphere of' Nz :'or 16 hr." Experimental Section? The solvent was removed under reduced pressure and the residue I , 1 '-Heptamethylene-fj,7-dimethoxy-1,2,3,~-tetrahydroiso- was dissolved i n CH2C12 and extracted successively with cold tliquinoline-2'-(o-carbomethoxyphenoxycarbonyl)-~~',7'-dime- lute HCI, saturated SaHCO3. and hrine. Drying (MgS04) and thoxy-l',2',3',4'-tetrahydroisoquinoline (4a) Hydrochloride. solvent removai yielded a yellow foam (7..1 g ) , Chromatography ,~ Method A. According t o t h e method of Verbiscar and A h ~ o d the on a column of neutral alumina provided purii'ied 5a (4.12 g. "dihydro-tetrahydro" isoquinoline intermediate 2.2HC11 (2.0 g. 50.7%) upon elution with Et20 + WCE t O H . . I n n / I(':lxHnzU,Oii 0.0036 mol) was suspended in 10 ml of H 2 0 and placed under NZ C. H. N.Mass spectrum: m / e 676 (M 1. atmosphere in a n ice-water bath, and a solution of NazC03 (0.768 Sodium amide 10.156 g. 0.004 molt was suspended i n 1M) nil 01 g, 0.00725 mol) in 2 ml of HzO was added with stirring. CHClR dr? T H F and cooled t o 0". A solution of isopropylideneglycero15 I23 ml) was then added, followed by the dropwise addition over 6 (0.528 g, 0.004 moli in 5 ml of T H F kvas then added with stirring min of a solution of o-carhomethoxyphenyl chloroformate (0.795 The mixture was then allowed t o warm to room temperature over g, 0.0037 mol) in 5 ml of CHCl3. The mixture was then stirred at 15 min under a slight vacuum in order to remove the generated ro(im temperature for 2 hr and worked up by separating the "3. A solution of the intermediate 5a (2.6 g, 0.0038 mol) in 10 layers and washing t h e CHC13 layer with water. Drying ( M g S 0 4 ) ml of T H F was then added dropwise over 5 min. T h e mixture was placed under N2 atmosphere and refluxed for 2.5 hr. Solvent removal under reduced pressure was followed by partitioning of the tWhere analyses are indicated only by symbols of the elements, analytiresidue between CH2Clz and H 2 0 . The usual washing and drying cal results obtained for those elements were within &0.4% of the theoretiof the organic layer afforded 2.8 g of crude oil. Column chromacal values (see also Table I). No melting point data are given since all of tography on neutral alumina (elution with Et20 + 1% EtOH) the compounds are noncrystalline. In general, compounds were purified by column chromatography and then converted to appropriate amorphow gave 5b (1.1g). salts for characterization and biological evaluation. Merck alumina (neu.4solution of 5b (:3,7 g, 0.0049 mol) in 200 ml of' CHC13 was sattral and basic aluminum oxide) and Mallinckrodt SilicAR (100-200 mesh) urated with HCI(g) and stirred a t room temperature for 6 hr. The were used in column chromatography and Analtech, Inc., Uniplates (alusolution was then shaken with excess 5% N a O H solution, followed mina G F and silica gel GF, 250 1.1) were used in appropriate eluting solby HzO and brine. Drying (MgSO4) and solvent removal gave vents for tlc monitoring of compound purity. Ir and nmr spectral data for crude 5c a s an orange oil (1.8 g. 61%). Chromatography on a colall compounds were consistent for the reported structures and were recordumn of CC-7 silica gel (elution with 8:l EtzO-EtOH) allowed the ed on Beckman IR9 and Varian A-60 (Mersi as internal standard) recordseparation of a purified sample (0.6 g ) , Treatment with sodium ing spectrometers, respectively. Mass spectra were recorded at 70 e\' on an borohydride in MeOH to reduce dihydroisoquinoline (from air oxLKB-9000 massspectrometer.
minum azide,12 followed by hydrolysis, to give the tetrazolylethyl derivative 5n. The N-sulfonic acid sodium salt 5p was synthesized in order to evaluate an analog having an anionic group attached directly to the nitrogen atom. It was prepared from l b and S03N(CH3)3 via the intermediate 50. Miscellaneous Analogs. It is well known that an c t phenylglycine side chain in penicillins and cephalosporins is associated with a superior degree of oral absorption.13 A bis( tetrahydroisoquinoline) of this type ( 5 r ) was prepared from lb ilia 5q, using the method of Spencer, f t aL1* The oxadiazole 10b was prepared from 9 and the appropriate oxadiazolethiol (Scheme 111), and the nitroso analog .is was obtained from l b via the method of Bumgardner. f>tai.l5 Fibrinolytic Activities. The modified in Liiuo~-inv i t r o dilute blood clot lysis assay, using male Long Evans rats, was used to evaluate the compounds (mixtures of isomers) .I Comparison of activities after ip injection (Table I ) again shows that N-Boc-N/-substituted intermediates (%a,e,g) have no fibrinolytic activity a t the screening dose of 20 mg/kg.l Mono-N-ethyl derivatives bearing an anionic group (5k,l,n and loa) retain good ip activity, compa2 rable to the parent reference standard drug la (MED mg/kg). In oral screening a t 100 mg/kg, no significant activity was seen with any of the analogs, with the possible exception of the thiophosphate 10a (see Table I). Although inactive when administered in Tween-HzO, PEG 400-Hz0, and DMAC-H20 vehicles, 10a consistently showed statistically significant fibrinolytic activity (60-6570 lysis) us. vehicle controls (30-35% lysis) when administered in 1:1 ethanol-water. The parent drug la showed no significant oral activity in any of the vehicles mentioned a t doses up to 250 mg/kg. Since a useful level of oral activity was not obtained in these derivatives, no attempts were made to assess the susceptibility of some of the side chains to hydrolytic and/or metabolic breakdown as discussed herein. In conclusion, our studies on the bis(tetrahydr0isoquinolines) have shown that structurally diverse N-monosubstituted derivatives, although maintaining high parenteral fibrinolytic activity in many cases, do not possess significantly altered absorption characteristics from the parent drug l a .
-
JournnIofMedicinal Chemist?, 1974. Vol. 17, No. 12 1251
Synthetic Fibrinolytic Agents. 2
Table I. N-Monosubstituted Bis(tetrahydroisoquinolines)and Intermediates nHCl OMe
MED, mg/kgb
n
Formula
Analyses“
iP
PO
4b
H H
1 1
5 10-20
> 100 > 100
5a
Boc
0
> 20
> 100
5c 5e
H
1 1
5
>20
5f
H
5t3
Boc
2 0
> 20 > 20
5h
1
51
H H H H
2 0 2
5- 20 5-20 5 5
> 100 > 100 > 100 > 100 > 100 > 100 > 100 > 100
5n
H
2
2- 5
> 100
5P 5s
H H H
0 2 1
5-20 -2 2- 5
> 100 > 200 >, 100
10s
H
0
-2
-100
10b
H
2
> 20
=. 100
4a
51
5k
5r
Boc
C3,H4,NzNa07PS
%See footnote ?. bDilute blood clot lysis assay (see ref 1 ) .C : calcd, 62.20; found, 61.75. N: calcd. 4.40; found, 3.96. Mass spectral analysis (see Experimental Section). pC: calcd, 63.15; found, 63.60. /C: calcd, 56.10; found, 56.52. XSee Experimental Section. hN: calcd, 6.10; found, 5.44. idation),’ followed by conversion to the HCI salt in the usual ride of 5f was prepared in the usual manner. Anal. manner, afforded 5c.HCI (0.74 g). Anal. ( C ~ ~ H ~ ~ N Z O X C* ,H C I () C ~ ~ H ~ I N ~ O J . C, ~ HHC , N. I) H, N. Mass spectrum: m / e 601 ( M i ’. I , 1’-Heptamethylene-ti,7-dimethoxy-1,2,3,~-tetrahydroiso1 , 1 ’-Heptamethylene-~i,7-dimethoxy-1,2,3,~-tetrahydroi~o- quinoline-2’-ethoxyacetyl-ti’,7’-dimethoxy-l’,2’,3‘,4’-tetrahyquinoline-2’-(n-propylaminoacetyl)-(i’,7’-dimethoxy1 ’,2’,3’,4’droisoquinoline (5h) Hydrochloride. Triethylamine (1.11 g, tetrahydroisoquinoline ( 5 0 Dihydrochloride. Triethylamine 0.011 mol) was added to a solution of I b (5.96 g, 0.0102 mol) in (1.32 g, 0.013 mol) was added with stirring to a solution of I b (6.0 CHzC12 (40 ml) and the stirred mixture was placed under NZand g, 0.010 mol) in 250 ml of CH2C12. T h e mixture was placed under cooled to near 0” in a n ice-HZO bath. A solution of ethoxyacetyl NZ atmosphere and cooled to near 0” in a n ice-HzO bath, and a chloride16 (1.35 g, 0.011 mol) in CHzClz (10 mi) was added dropsolution of chloroacetyl chloride (1.43 g, 0.013 mol) in 25 ml of wise over 20 min. Subsequent stirring a t room temperature for 19 CHzClz was added dropwise over 15 min. After stirring a t room hr, solvent removal, and work-up in the usual manner yielded temperature for 1 hr the mixture was poured into ice-HzO and crude 5g (6.36 g, 93%). Column chromatography (neutral alumithe layers were separated. The aqueous phase was extracted with na, elution with E t 2 0 + 1% EtOH) gave a pure sample. Anal. a second portion of CHzC12 and the combined organics were ( C ~ S H ~ ~ N Zc, OHS,)N. washed successively with cold dilute HCI, bicarbonate solution, Treatment of’ crude 5g (5.28 g, 0.0079 mol) with 97% formic and HzO. Drying (MgSO4) and solvent removal gave 5d (6.0 g) of acid in the usual manner gave 5h (3.63 g, 82%) and column chrosufficient purity for further elaboration. matography on neutral alumina gave purified material (1.74 g) A solution of 5d (3.81 g, 0.0058 mol) in excess n-propylamine 2% EtOH. TICrevealed the presence of upon elution with E t 2 0 (25 ml) was refluxed in a n atmosphere of Nz for 4 hr. The excess some dihydroisoquinoline.1 necessitating reduction with NaBH4 amine was distilled off under reduced pressure and the residue in MeOH prior to conversion to the HCI salt (5h.HC1, 1.93 g) in was partitioned between E t 2 0 (two portions) and H 2 0 . T h e usual the usual manner. Anal. (C33H4gNzOe.HCl) C, H, N. washing, drying, and solvent removal procedures afforded 3e a s I , 1 ’-Heptamethylene-6,7-dimethoxy-I ,2,3,&tetrahydroisoa n orange syrup (3.51 g, 8970). Column chromatography on neuquinoline-2’-ethoxyethyl-(i’,7’-dimethoxyI ’.2’,3’,4‘-tetrahydrotral alumina provided purified .ie (2.82 g) upon elution with E t 2 0 isoquinoline (5i) D,ihydrochloride. T o a stirred ice-cooled solu+ 5% EtOH. T h e HCI salt was prepared in t h e usual manner. tion of 1 M BH3 in T H F (5.0 ml, 0.005 mol) in dry T H F (40 mlj A w l . (C3gHogN307*HCI)C, H, N . under N2 was added a solution of 5h (0.86 g, 0.0015 mol) in T H F T h e free amine 5e (1.75 g, 0.0026 mol) was dissolved in 50 ml of (40 ml) over 20 min. T h e mixture was then refluxed for 22 hr, 97% formic acid and stirred a t room temperature under NZfor 2 cooled to room temperature, and then treated successively with 3 hr. T h e usual work-up provided 5f (1.41 g, 94.8%). A purified N HCI (4.0 ml) and H 2 0 (40 ml).T h e solution was briefly heated sample (0.47 g) was obtained by column chromatography on neuto reflux and the T H F was then removed under reduced pressure. tral alumina (elution with E t 2 0 + 2% E t O H ) . The dihydrochloBasification ( 1 N NaOH), extraction with CHZCIZ,and the usual
+
12.52 Journal of Medicinai Chernlstty. 1974, C b l . i 7. Y o . i2
isolation procedure gave j i (0.84 g, quantitative) a s a pale yellow oil that appeared homogeneous on tlc. Treatment with HCI(g) in the usual manner afforded 5i.2HCI (0.493 g ) . A n a / . (C33H50N2O5.2HCI) C. H, N . Mass spectrum: r n / ~555 (%I1. 1 , I '-Heptamethylene-6,7-dimethoxy-l,2,3,l-tetrahydroisoquinoline-2'-($-carboxyethyl)-6',7'-dimethoxy1',2',3',4'-tetrahydroisoquinoline Sodium S a l t (.5k). A solution of ethyl acrylate (0.55 g, 0.0055 mol) in absolute E t O H (5 ml) was added dropwise with stirring under Nz atmosphere to a solution of I h (2.77 g. 0.00475 mol) in absolute E t O H (75 m l ) . Triethylamint~( 3 drops) was added and the mixture was refluxed tor 60 hr. Stripping of solvent and excess acrylate under reduced pressure. f'ollowed by column chromatography of the crude product on C C - 7 silica gel, gave the ester 53 (2.3 p. 70.8%) upon elution with E t 2 0 2% EtOH. The ester 5j (1.46 g, 0.00214 mol) was dissolved in 95% EtOH (60 ml), KOH pellets (0.33 g. 0.0059 mol) were added. and tlie mixture was stirred at room temperature for 3.5 hr. After solvent removal, the residue was dissolved in HzO and extracted with Et20 to remove any neutrals. The aqueous layer was acidified with concentrated HCI and then heated for 2 hr a t 50". The E t O H was removed under reduced pressure, brine was added to the remaining aqueous slurry, and the mixture was extracted with two portions of CHzC12. The usual isolation procedure yielded crude 3k.2HCl (1.36 g) a s a foam. Purification was effected tbia ion-exchange column chromatography on Dowex SOW-X1 resin (Na form).l7 A solution of Bk.2HC1 (0.668 8 ) in a minimum volume of p H 6.82 phosphate buffer was applied to the column and the purified sodium salt 3k (0.359 g) was eventually eluted with pH 8.37 buffer (60%) n-PrOH (40%). .Anal /C32H45N20&at
+
quantitatively 5p a s a friable solid. Anal. (CzgH41NaNzOrS) (', H. N, S. I,1 '-Heptamethylene-fi.7-dimethoxy-1,2,:3,l-tetrahydroiso q u i n o l i n e - 2 ' - ( < >- p h e n y l g l y c y l ) - f ; ' , 7 '-dimethoxy-l'.?',3', 1'-te trahydroisoquinoline ( 3 )Dihydrochloride. .A sulution ot ethyl chloroformate (1.05 g, 0.00966 mol! and . ~ . Y - d i m e t h y l b e n z ? l a mine ( 6 drops, catalyst) in dry CHzCI2 (150 mlJ kvas placed under Nz atmosphere and cooled to 0" in a n ice-halt hath. iii- l ~ r 3 - [ ( l carbomethoxyprope~i-L'-?.l)aniin~)]phen~l acetate14 (2.62 c, 0.00'366 m o l ) was added with stirring. producing a ivhite precipitate. After .5 1 0 min a sr1,irion of I b (5.06 g. 0.00868 mol) in CH2Cl2 (100 m i ) was added s l o w i ~ .keeping the reaction temperature helow 5'. After the additivn was complete the mixture was refluxed for 16 hr, lollowed by filtration and removal of solvent t i l give trude .iq (7.68 g ) . Treatment with 97% formic acid and then NaOH solw tion in the usual manner afforded crude 5r. containing the monoquinoline derivative as thi. main imp:irit? pectrum. r n / r ,?A), ('hromatograph\ on neutral alumina yielded purified Sr (1.06 g ) upon elution Liith Et20 + 5% EtOH. Conversion t o the dihydrochloride salt \vas carried o u t in the usual manner. .4nni ( C ~ ~ H ~ P - V ~ O ~( '. ,~H. H('I)
N.
I , 1 '-Heptamethylene-(i.7-dimethoxy-1,2,:~,l-tetrahydroisoquinoline-2'-nitroso-6',i'-dimethoxy-l,2',3',4'-tetrahydroisoquinoline ( 5 s ) Hydrochloride. According to the method of H u m . gardner. c t o i ,15 :l-nitro-9-nitrosocarbazole(Enstman. 4 . 0 p. 0.0166 mol) and Ih 1 , 4 5 g. 0.00772 mol) were stirred in ('6H,j under NZ a t reflux f o r 15 min. Cooling tu 10 15". removal of the solid :l-nitrocnrbazciIe by filtration, and stripping
