;\larch 196s Experimental Section4 The physical properties, yields, arid analyses are listed in Table I. 2-Carboxy-6,8-dichloro-~-chromone (I).-A mixture of 11.8 g (0.080 mole) of ethyl oxalate and 15.0 g (0.075 mole) of 3,sdic.hloro-2-hydroxyacetophenoiiej i r i 200 nil of aiihydroiis Et20 was added, over a period of 30 min, to a vigorously stirred srispeiibioii of XaOEt (13.6 g, 0.2 mole) in 100 nil of anhydrous Et&. The mixture was kept at 30-25" for 0.5 hr, heated under reflux for 2 hr, cooled, and filtered. The sodium salt was suspended in 360 ml of a mixtiire of AcOH-concentrated HC1 ( + j : land ) heated under reflux for 2 hr. The reaction mixt'ure was cooled aiid the insoluble solid was collected. Recryst'allizatioii from AcOH gave 10.5 g (56'5,) of white needles. Esters. General Method.-Coilcentrated H2S04 ( 2 ml) was added slowly to a snspensiori of I (2 g) in 20 ml of the appropriate alcohol. The mixture was refluxed for 4 hr. The ester, which precipitated on cooling, was collected and washed (NaHCOJ, ETp() ), 6,8.Dichloro-y-chromone-2-carbonylChloride (VII).--Tlie acid I was suspeiided i l l a mixture of 5 g of S0Clz and 6.0 1111 of I ,2-dichloroethaiie and heated with occasional shaking under reflux for i-8 hr. The hot mixture was filtered arid the residue was extracted twice with hot petroleum ether (SO-SO"). The filtrate and the ethereal extrack were pooled aiid evaporated in vacuo. The residue was recrystallized from petroleum ether; yield 240 mg (670) of pale yellow prisms.
2-(N,N-Diethylcarbonamide)-6,8-dichloro-y-chromone (VI).Diethylamine (0.,5 ml, excess) was added to a cold suspension of 140 mg of VI1 in 3 ml of anhydrous CcH,. The mixture was kept at room temperature for 30 miri and then refluxed for 30 min. The solvent was removed, and the residue was treated with H 2 0 , filtered, arid washed (HZO). The solid, recrystallized from EtOH, gave 100 mg (647,) of white needles.
Acknowledgment.-The author wishes to thank Professor Dr. Armando Novelli for his many helpful suggestions. This work was carried out with a grant from the C. K.I. C. y T. (4) .111 melting points were taken in capillaries and are uncorrected. \$-here analyses are indicated oniy by symbols of the elements, analytical results obtained for those elements mere within =t0.4YOof t h e theoretical values. ( 5 ) .I. R.Sen and P. 11.Uhargara, J . Indian Chem. Soe., 26, 366 (1949).
Experimentally- Induced Phenylketonuria. 111. Inhibitors of Phenylalanine Hydroxylase Related to Esculetin I. D E G R ~ M ~ I I CIEL H CORY,TIT. A. S I U N ~ E R , ~ I Y C. N THEISEN, ~ AND C ~ o z o MITOM&
JOSEPH
~
commu~iication.~The subject of this paper is a further investigation, both in vitro and in vivo, of hydroxylated coumarin compounds related to esculetin. We began our structure-activity investigation by preparing various 3- and 4-subst ituted G,'i-dihydrox)-coumarins. We found that, i 7 i vitro, the +methyl, 3ti-butyl, and &phenyl analogs were niore potent iiihibitors of phenylalanine hydroxylase than esculetin. The 4-ethyl-, ?+propyl-, and isopropyl-substituted compounds were about as active as esculetin, while the activity was considerably diminished for the :tlrc,4y-~-mcthox!-phen3.1 formate i i i H3P04. Tho rwiil t a n t G-nic~thosy-7-h~droxycouniariri~ were cleaved I\ i t 11 hot HBr to t h r 6,7-dih!-droxycourrinriris (Table 111). G-Hydroxyhtionfi of 3,7-tlimeth( li2S2Oefollo\wtl by ether liydrolysi\ nfforded 5,G,7-trih i dro?c?couni:iriri. Experimental Section ~ I c l l i l i gpoiiit\ wei e obtained with a Fisclier-Jolins apparatiiale corrected. hVhere analysei are indicated only by symbol> of the elements, analytical resiilts obtained for thoze elements were within 10.47; of the theoretical valueh. :itid
.j,(j-Uiliydrux>--m d G,T,S-(rili~~tlrcis~-4-1ii~~ I i ~ l c i i r ~ ~ n ~WCI ~ r ~(' i r i i prepared by Ihe method of Xaili aiitl Thakcir.5 ( ~ ~ 7 - I . ~ i ~ i y i l r i i ~ ~ . 4-mei hyl-, i,8-dihydriisy-4-1iiet h>-l-, :ii id 5-liydroxy-4-1iiel hylcouniariii were obtained from Ildrich Chemical Co. 5,7-Dimethoxy-6-hydroxycoumarin.--To 2.06 g ( I O n i n i o l e h t of ~j,i-dimethoxycoumarin( A1dric.h Chemic~al Co.) \vas :tdtletl 40 nil of 105; KOH arid 3 tlrcips of pyridilie. The holritioii \v:~s chilled iii an ice bath and 3.12 g (19 mmoler) of H 2 0 \vas slowly added. The resiiltiiig aolrit' 16 hr ai room teniperatiire, aridified ( I l C l j i o (three 50-nil portions i i f E20) tcJ remove Concentrated HC1 (13 nil) mid 1.0 g of &-a11 the reiiilting mixtiire waa hea,ted O I I a steani t) :tiid eatracted (three 50-1111p o r t i o l i n ) with EtyO. The estract w:i> dried aiid evaporated in m m o i(i!.ield :r briin-ri seniibolitl. ' h v i i recrystallixatioirs (EtO.\t*j g:tw 0.112 g (5.11'; ), r n j 1 172 17:;'. -Incil. (CIIH:&) C, IT. 5,6,7-Trihydroxycoumarin.-?l Ill'(; of 0 . I N g ((Mi0 iiimule) of 5,i-dimethoxy-6-hydri iirriarili aiid X J nil of rriricwitrated HBr was stirred a t r for 2 hr, cooled, arid diluted with €I& ( l a d). The aqueous mixtiire &-asex1r:rc:led \villi EtOAc (three 20-ml p) :iiitl tivied ( A I~:tOAcwas evaporated in ~ C I ~ Othe , prodrirt \*-a. ( EtOA4c),yield 0.067 g (5Sz,), mp 25y, .I. O r y . Chem., 26, 3213 ( 1 9 6 l j . (H) 1'. I,. Saalinry. T . K. Seshadri, and T. It. Thiruvengadarn, I'roc. l r i r i t r m .led. d c i . . 33, 11 ( l % j l ) . 1,;)
17) I{, A l . S a i k and V. AI. ' l ' l ~ a k u r , J . 0 r . g . C'hen~.,22, 1050 (,li!
