Notzel, Marcus W. published the artcileCyclopropyl building blocks in organic synthesis. 66. A new and efficient access to thiazoline-4-carboxylates and cysteine derivatives incorporating cyclopropyl groups, SDS of cas: 6972-05-0, the publication is European Journal of Organic Chemistry (2001), 3025-3030, database is CAplus.
Under basic conditions (NaHCO3, MeCN), thiocarboxamides, including N,N-thioureas, cleanly undergo Michael addition onto 2-chloro-2-cyclopropylideneacetates, attacking through the sulfur, and this is followed by an intramol. substitution to afford 5-spirocyclopropane-annelated thiazoline-4-carboxylates [I; R1 = H, Me, Et, PhCH2OCH2CH2, R2 = (un)substituted Ph, Me, NMe2, NMePh, etc.] in 37-92% yields. I are cysteine derivatives that possess a cyclopropyl or substituted cyclopropyl group in place of the gem-dimethyl-substituted ¦Â-carbon atom of penicillamine; they can be hydrolyzed to the hydrochloride salt of the amino acid by heating in acid. Under acidic conditions (CH2Cl2, HCl), the Michael adducts of thioamides onto 2-chloro-2-cyclopropylideneacetates are formed in high to virtually quant. yields. When treated with NaHCO3 in MeCN, the adducts cyclize to thiazolinecarboxylates (51-82%), but in the presence of Ti(OiPr)4 they form spirocyclopropane-annelated thiazinones (19-88%).
European Journal of Organic Chemistry published new progress about 6972-05-0. 6972-05-0 belongs to catalysis-chemistry, auxiliary class Thiourea,Amine,Aliphatic hydrocarbon chain,Amide, name is 1,1-Dimethylthiourea, and the molecular formula is C3H8N2S, SDS of cas: 6972-05-0.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia