2 102
S. A. HARRIS,K. MOZINGO, D. E. WOLF,A. N. WILSONAND KARLFOLKERS
Anal. Calcd. for CIO€€UNSO&:C, 49.16; H, 6.60; N, 11.46. Found: C, 49.21; H, 6.81; N, 11.25. Resolution of I( +)-Arginine Salts of dl-Biotin.-A mixture of 1.44 g. of dl-biotin and 1.15 g. (10% excess) of I(+)-arginine was dissolved in 20 ml. of water and the solution was diluted with isopropyl alcohol. Crystallization was allowed to proceed in the refrigerator overnight. The crystals were collected on a filter and washed with acetone; m. p. 214-218" (micro-block); [ a ] $ '+49.09" ~ (c, 1.039 in water); yield 1.13 g. (92%). The I(+)-arginine salt of biotin when pure had the following properties: m. p. 228-230' (micro-block); [ a ] * ' D $59.9' (c, 1.37 in water). Anal. Calcd. for ClsHa~NsOaS:C, 45.91; H, 7.23. Found: C, 46.25: H, 7.51. One and nine-hundredths grams of the crude l ( + ) arginine salt was recrystallized twice from aqueous isopropyl alcohol; [ a ! ] ' & +57.2' ~ (c, 1.747 in water). The purified salt was dissolved in 10 ml. of water and acidiiied with dilute hydrochloric acid. The crystalline biotin was collected on a filter, washed with water and dried; m. p. 229-231' (micro-block); a mixture of this sample with biotin of natural origin melted without depression; [ c y ] 2 6 $88.8' (c, 1.025 in 0.1 Nsodium hydroxide); yield 0.51 g. (80%). Further purification, was accomplished by suspending the biotin in 20 ml. of hot water, adding just enough dilute sodium hydroxide solution to dissolve the solid, then acidifying with hydrochloric acid. The pure crystalline biotin melted a t 229-231'; [a]*'~ $90.4O (c, 1.87 in 0.1 N sodium hydroxide); yield 0.44 g . (64% overall).
VOl. 67
Anal. Calcd. for C~OHISN~OSS: C, 49.16; H, 6.60; N, 11.46. Found: C, 49.07, 49.35; H, 6.46, 6.47; N, 11.42.
Acknowledgment.--The authors wish to express their thanks to Messrs. D. F. Hayman, R. N. Boos, Leonard Rosalsky and Edward Thornton for carrying out the microanalyses.
summary
~
&Biotin has been resolved by three independen t methods, The fractional crystallization of the d(-)mandelic acid esters of dl-biotin led to the isolation of biotin. From the E(+)-mandelic acid esters, 1-biotin was obtained. Quinidine methohydroxide was found to be a satisfactory reagent for the separation of 1-biotin from its enantiomorph. Biotin was obtained from the mother liquor salts. The I( +)-arginine salt of biotin crystallized as the less soluble salt from the mixed dl-biotin salts of I(+)-arginine. Decomposition of the salt gave biotin. This resolution of dl-biotin is the most satisfactory one. RECEIVED AUGUST17,1945
RAHWAY, NEWJERSEY
__
[CONTRIBUTION FROM
THE
RESEARCH LABORATORIES, MERCKA N D Co., INC. ]
Biotin. VII. A Stereochemical Correlation of &Biotin, dl-Allobiotin and dl-rpiAllobiotin BY STANTON A. HARRIS, RALPHMOZINGO, DONALD E. WOLF, ANDREWN. WILSON AND KARLFOLKERS A stereochemical correlation of dl-biotin, dlallobiotin and dl-e@*-allobiotin'and of the three intermediate racemic methyl esters of 3-acetamido - 4 - benzamidotetrahydro - 2 - thiophenevaleric acid2 has been accomplished. This was effected by the use ,of the sulfur hydrogenolysis reactiona*' with Raney nickel catalyst. T h s application of this reaction is illustrated by reactions I11 3 IV and I 3 V. A tetrahydrothiophene which is substituted in the 2 , 3 and 4 positions could exist in eight stereoisomeric forms. Four of these forms are represented by formulas VIIId, f, g and h in Diagram I; the other four forms are enantiomorphic to the ones shown and do not need to be illustrated for the purpose of this discussion. If the sulfur atom were replaced by hydrogen atoms, the asymmetry about carbon atom 2 would be lost. Two of these forms are represented by formulas IXj and k; the other two enantiomorphic forms are not illustrated. The racemates as well as the individual isomers may be used to show these (1) Harris, Mozingo, Wolf, Wilson. Artb and Folkers, THIS 08, 1800 (1944). (2) Harris, Wolf, Mozingo, Arth, Anderson, Easton and Folkers, zbid., 6?, 2098 (1945). (3) Mozingo, Wolf, Harris and Folkers. rbrd., 66, 1013 (1943) (4) du Vigneaud, Melville, Folkers, Wolf, Mozingo, Kcresztesy and Harris, J . B i d . Chcm., 116, 475 (1942); Melville, Dittiner Drown and du Vigneaud Science, 98, 497 (1943) JOURNAL.,
NHCOCeH5
I
THCOCsH5 CH-CHNHCOCH3
I
I
CHs
Ni(H) CH--CHNHCOCHa
CH(CH2)dCOzH
- I
I
CH, (CHz)sCOz€I
\s/
v
I
& I
Ba(OH), NH2
Ba(OH12
KHz
NHz
NH2
I I
CH-CH I
I
I
FH-CH I
L
