F O R M A T I O N O F 2 , 3 , 4 , 5 - T E T R A D E H Y D R O B I O T I N

F R O M a ' - S U L F U R - C O N T A I N I N G D E R I V A T I V E S O F

c ~ - O X O D E H Y D R O D E S T H I O B I O T I N E T H Y L E S T E R

S. ?. Z a v ' y a l o v , I . A. R u b t s o v , L . L. Z h e l e z n a y a , A. B. P a v l o v a , a n d N. A. R o d i o n o v a

UDC 542.91:547.9:577.15

The successive t rea tment of the thiuronium salt (I) with alkali and hydrochlor ic acid gave [1] the hy- drolysis and cyclization product (CP), which was assigned the s t ructure of 2,6,3,4-tetradehydrobiotin (II). tn the present paper, on the basis of comparing the NlVIR, IR, and UV spectra, and also the mixed melting point, it was shown that the CP is identical with the 2,3,4,5-tetradehydrobiotin (llI) that was synthesized previously by start ing with thiophene [2, 3]. As it proved, (III) is formed in higher yield by the cyclization of the ethyl es te r of N,N-diacetyl- a - o x o - oz '-(acetylmercapto)dehydrodesthiobiotin (IV) under the influence of alkali and hydrochlor ic acid. When heated with a mixture of acetic and hydrochlor ic acids, (IV) under- goes N-deacetylat ion and is not converted to (Ill).

In a s imi lar manner , l ' -methyl -2 ,3 ,4 ,5- te t radehydrobio t in (V) is formed by the cyclization of the ethyl es ter of 1 -me thy l - a -oxo-a ' - ( ace ty lmercap to )dehydrodes th iob io t in (VII) and subsequent react ion of the intermediate bromide (VIII) with CH3COSK

0 0 I[ 113'

CH~CON NCOCH~ then HC1/H2(~ R'

c r u x \ ~ / \ 6 , , . 16

] ~ 2 CH~CH~CH~CH2C00H (I) X=SC(=NH)NH~.HBr (III) R'=H 1"1

I ( IV ) X=SCOCH~ (V) PJ=CH8 [NaOH/HzO then HC1/H20

o o o II [I ~ I[

NH NH CH H ---~ CHiN

I 1 k o C ~ S c o c g s a' Cg~ R

CHsCOSK

O

/ \ NH - - - - , CI~N NH

\ \ C 2Br R CH2SCOCHs R

(Ix) (v~t) (vm) (vl)

R = CO(CH2)4COOC~H5

/\ HN NH

i--t Ks/\

CH(CH2)~COOH (H)

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the ~JSSR. Izvestiya Akademii Nauk SSSR, submitted December 20, 1972.

Translated from Seriya Khimicheskaya, No. 7, pp. 1679-1681, July, 1973. Original article

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EXPERIMENTAL METHOD

The UV spectra were taken in alcohol on a Specord UV-VIS instrument. The IR spectra were taken as KBr pellets on a UR-20 instrument. The NMR spectra were taken on a DA-60-1L instrument, using HMDS as the internal standard.

2,3,4,5-Tetradehydrobiotin (III). To a suspension of 1 g of the ethyl ester of N,N-diacetyl-a-oxo- (~'-(acetylmereapto)dehydrodesthiobiotin (IV) [4] in 5 ml of water was added I0 ml of 10% KOH solution, after which the mixture was stirred for 2 h at ~20~ acidified with 1 N HC1 solution, and allowed to stand for 12 h at ~20 ~ The precipitate was filtered and washed with water. We obtained 0.55 g (94%) of (Ill), mp 215-220 ~ or 0.3 g (60%) of (III), mp 241-243 ~ (from water), Rf 0.62 (TLC, silica gel G, 4:1 alcohol -ethyl acetate, detection of spot with 12 vapors). Ultraviolet spectrum: kma x 262 and 306 nm (e 15,800 and 777). Infrared spectrum (v, cm-l): 1670, 1730 (C=O). NMR spectrum (pyridine, 5, ppm): 1.67 (CH2CH 2, multiplet), 2.36 (CH2C=C, multiplet), 2.70 (CH3COOH, multiplet), 6.15 (HC(S-)=C, singlet), 11.40 (2NH, broad singlet). The obtained compound fails to depress the mixed melting point with either the CP [I] or an authentic sample of (III), and has the same spectral characteristics as they do.

Ethyl Ester of 1-Methyl-c~-oxo-a'-(acetylmercapto)dehydrodesthiobiotin (VI). A mixture of 0.53 g of the ethyl ester of 1-methyl-(~-oxodehydrodesthiobiotin (VII) [5] and 0.36 g of N-bromosuccinimide in 15 ml of CCI 4 was heated at 90 ~ for 2 h; the separated succinimide was filtered, the filtrate was evapo- rated in vacuo, the residue was treated with ether, and the precipitate was filtered. The obtained ethyl ester of 1-methyl-c~-oxo-(~'-bromodehydrodesthiobiotin (VIII) (~0.7 g) was stirred for 1 h at ~20 ~ with 0.5 g of CH3COSK in 6 ml of absolute acetone, evaporated in vacuo to dryness, and the residue was treated with water and then extracted with ethyl acetate. After evaporation of the extract in vacuo the residue was rubbed with 3 ml of alcohol. The precipitate was filtered and then reerystallized from alcohol. We ob- tained 0.2 g (30%) of (VI), mp 137-138 ~ Rf 0.72 (Silufol UV254, 49 : 1 acetone-water, detection of the spot in UV light). Ultraviolet spectrum: Xma x 308 nm (s 10,500). Infrared spectrum (v, cm-l): 1730 (CO0 �9 C2H5), 1690 (SCOCH3), 1670 (NHCONH), 1600 (C=C). NMR spectrum (pyridine, 5, ppm): 1.00 (CH3CH2, triplet), 1.74 (CH2CH2, multiplet), 2.20 (CH3COS, singlet), 2.39 and 2.71 (2CH2CO, multiplets), 3.18 (CH3N, singlet), 3.98 (OCH 2, quadruplet), 4.45 (SCH2C~C, singlet). Found: C 52.22; H 6.47; S 9.45%. C~5H22 �9 O5N2S. Calculated: C 52.60~ H 6.43~ S 9.36%.

l-Methyl-2,3,4,5-tetradehydrobiotin (V). To a suspension of 0.i g of (VI) in 1 ml of water was added 1 ml of 10% KOH solution, after which the mixture was stirred at ~20 ~ for 2 h, filtered, the filtrate was acidified with 1 : 1 HCI solution, allowed to stand at ~20 ~ for 12 h, and the precipitate was filtered and re- crystallized from 70 ml of water. We obtained 0~ g (270/0) of (V), mp 214-217 ~ Rf 0.69 (Silufol UV254, 2 : 1 ethyl acetate-alcohol). Ultraviolet spectrum: kma x 240 and 300 nm (e 16,100 and 670). Infrared spectrum (v, era-t): 1690 (COOH), 1660 (NCON). NMR spectrum (pyridine, 5, ppm): 1.72 (CH2CH 2, mul- tiplet), 2.33 (CH2C=C, multiplet), 2.67 (CH2COOH, multiplet), 3.20 (CH3N, singlet), 6.10 (HC(S-)=C, singlet). Found: C 51.94; H 5.66; S 12.24%. CIIHI403N2S. Calculated: C 51.96; H 5.54; S 12.60%.

Ethyl Ester of (~-Oxo-c~'-(acetylmercapto)dehydrodesthiobiotin (IX). A mixture of 1 g of (IV) and 0.i ml of conc. HCI in I0 ml of CH3COOH was refluxed for 5 h, evaporated in vacuo, and the residue was treated with ether and the crystals were filtered. We obtained 0.61 g (76%) of (IX), mp 119-121 ~ (from alcohol), Rf 0.66 (silica gel G, acetone). Infrared spectrum (v, era-l): 1730 (COOC2H5), 1720 (C=O), 1693 (SCOCH3), 1660 (C=O), 1620 (C=C). Found: C 51.34; H 6.23; S 10.12%. CIcH20OsN2 S. Calculated: C 51.26; H 6.14; S 9.76%. The obtained compound gives a red color with FeCI 3, which in(licates the presence of the N-unsubstituted 2-imidazolinone ring in its molecule.

We express our gratitude to B. P. Fabrichnyi for supplying the sample of (HI).

CONCLUSIONS

The successive action Of alkali and hydrochloric acid on the ethyl esters of N,N-diacetyl- and l-methyl-~-oxo-c~'-(acetylmercapto)dehydrodesthiobiotin, respectively, gives 2,3,4,5-tetradehydrobiotin and its l'-methyl derivative.

1.

2. 3.

LITERATURE CITED

I. Isaka, K. Kubo, M. Takashima, and M. Murakami, Yakugaku Zasshi, 8__88, 422 (1968). L. Cheney and J. R. Piening, J. Am. Chem. Soe., 67, 729, 731 (1945); 6__66, 1040 (1944). B. P. Fabrichnyi, I. F. Shaiavina, and Ya. L. Gol'dfarb, Dokl. Akad. Nauk SSSR, 162, 120 (1965).

1642

4o

5.

N. A. Rodionova, M. P. Unanyan, G. V. Kondrat'eva, S. I. Zav'yalov, and V. V. Filippovl Izv. Akad. Nauk SSSR, Ser. Khim., 660 (1970). S. I. Zav'yalov, L. L. Zheleznaya, and A. B. Pavlova, ibid., 1416 (1973).

1643