Sulfinic acids and related compounds. 13. Unsymmetrical disulfides based on methyl 4-mercaptobutanesulfinate and 4(S)- or 4(R)-mercaptoprolines

Abstract

In a study of disulfide-sulfinates containing prolylthio moieties epimeric at C-4, the OH group of N-acetylated 4(R)-hydroxy-2(S)-pyrrolidinecarboxylic acid ("írans-4-hydroxy-L-proline", 3) was converted to an epimeric SH group (11) by replacing a 4-O-tosyl group with PhCH2S (to give 5) and debenzylating. Reaction of 11 as the disodium salt with 1,2-dithiane 1,1-dioxide (2) replaced the H of the SH with S(CH2)4S02Na to give a disulfide-sulfinate salt (9). Since 9 was unstable in solution, with conversion of disodium 4,4'-trithiobis(butanesulfinate) (22) to the diester 23 as a model, 9 was converted to the disulfide-sulfinic ester 10. Subsidiary peaks in the 13C NMR spectra of N-acetyl derivatives were shown to originate from rotamers. Similarly, the epimeric 4(S)-hydroxyproline ( 16) was converted to the 4(R)-mercaptoproline epimer (19) of 11, which was converted in turn to the disulfide-sulfinate epimer (21) of the sulfinic ester 10. The two disulfide-sulfinate esters 10 and 21 were stable under ambient conditions and began to disproportionate to the two symmetrical disulfides in refluxing ethyl acetate in 1.5 (21) toca. 7 h (10). The sulfinic esters 10,21, and 23 seem likely to serve as biological precursors of sulfinate and thiolate salts, which may be useful for several purposes.

Novel Cyclic Analogs of Angiotensin II with Cyclization between Positions 5 and 7: Conformational and Biological Implications

“…Homoserine was purchased from Schweizerhall (South Plainfield, NJ) as were N -α - Boc- S -(4-methoxybenzyl)cysteine and N -α-Boc-(4-MeBzl)homocysteine. N -α - Boc-Pro( cis -4- S -MeBzl) and N -α - Boc-Pro( trans -4- S -MeBzl) were prepared based on the literature or by the more efficient stereoselective procedure of Kolodziej et al N -α - Boc-Pro( trans -4-NH-Fmoc) was prepared according to the literature . Other Boc-amino acids and HOBt were purchased from Advanced ChemTech (Louisville, KY).…”

The Chemistry of Organic Polysulfanes R−Sn−R (n > 2)

“…[97][98][99] Bis(sulfinato)trisulfanes may be converted to the corresponding dialkylesters by reaction with either diazomethane or a solution of BF 3 in diethyl ether. 100 When sodium polysulfide is applied in eq 66, the resulting polysulfanes according to eq 67 contain up to six sulfur atoms. However, the bis-(sulfinato)polysulfanes with more than four catenated sulfur atoms are unstable in water, and elemental sulfur is slowly precipitated.…”

“…Sulfinate compounds of this type are water soluble and may be used as antiradiation drugs (see Section VII.D). − Bis(sulfinato)trisulfanes may be converted to the corresponding dialkylesters by reaction with either diazomethane or a solution of BF 3 in diethyl ether . When sodium polysulfide is applied in eq 66, the resulting polysulfanes according to eq 67 contain up to six sulfur atoms.…”

Synthesis of Dihydrooxepin Models Related to the Antitumor Antibiotic MPC1001

“…The starting point was commercially available 4-hydroxy- l -proline 5 , which was converted by conventional methods , into the fully protected derivative 8 (Scheme ), and the ester group was then changed into an aldehyde 15 by reduction to the alcohol level and reoxidation ( 8 → 9 ), so as to set the stage for introduction of the C(1)−C(3) segment of the dihydrooxepin ring. To this end, aldehyde 9 was treated with ( Z )-2-ethoxyvinyllithium , to afford the C(4) epimeric alcohols 10 (ca.…”