92367-87-8Relevant articles and documents
Microwave-Assisted Synthesis of 2-Substituted 2-Thiazolines and 5,6-Dihydro-4 H -1,3-thiazines
Bisceglia, Juan A.,Kilimciler, Natalia B.,Mancinelli, Michele,Mollo, María C.,Orelli, Liliana R.
, p. 1666 - 1679 (2020/06/01)
An efficient and general method for the synthesis of 2-substituted thiazolines and 5,6-dihydro-4 H -1,3-thiazines is developed via microwave-assisted ring closure of ω-thioamidoalcohols promoted by ethyl polyphosphate (PPE). The cyclization reaction involves an S N 2-type mechanism and features the advantages of very short reaction times, high yields and a predictable stereochemical outcome. The acyclic precursors are prepared in high overall yields by an improved diacylation-thionation-saponification sequence from commercially available ω-amino alcohols. The whole process is metal-free and operationally simple.
Reaction of Chromium (Fischer) Carbenes and Sulfilimines
Alcaide, Benito,Casarrubios, Luis,Dominguez, Gema,Sierra, Miguel A.
, p. 3886 - 3894 (2007/10/02)
The photochemical reactions of alkoxychromium (Fischer) carbenes and sulfilimines lead to imidates in fair to excellent yields.Aromatic, heteroaromatic, and alkylsulfilimines, the latter bearing functional groups such as cyano, sulfone, ether, ester, and dioxolane groups, gave the corresponding imidates in good to excellent yield.However, acyl- and sulfonyl-substituted sulfilimines did not react with chromium carbenes, except for sulfilimines bearing ethoxycarbonyl and phthalimidylamino groups.A variety of differently substituted chromium carbene complexes bearing alkyl, cycloalkyl, styryl, allyl, and alkynyl groups attached either at the carbene carbon or at the oxygen also gave imidates in good yields.For α,β-unsaturated carbenes, the exclusive 1,2-addition of the sulfilimines nitrogen was observed at room temperature, in contrast to the behavior of other nitrogen nucleophiles which are reported to add in 1,4-fashion under these reaction conditions.In turn, optically active imidates of the type ArN=C(OR*)Me can be prepared efficiently by utilizing the corresponding chiral alkoxy group on the carbene moiety.The reactions above also occur in the dark but reaction times are considerably longer.N-Halosulfilimines reacted with alkoxychromium carbenes to yield N-acylsulfilimines instead of the expected N-haloimidates.Based upon a set of thermal and photochemical reactions between N-haloimidates and diphenyl sulfide in the absence of chromium complexes, the complex (CO)5CrNCMe is proposed to be responsible for this novel reaction of N-haloimidates and diphenyl sulfide.
Reactions with Aziridines, 45. - Arene Hydrides, 5 Reversibility of Carbonyl Attack on N-Benzoylaziridines Prior to Ring Opening by Carbanions. - Strong Influence of the Gegen Ion
Mall, Thomas,Stamm, Helmut
, p. 1349 - 1352 (2007/10/02)
A previous report had shown that anthracene hydride AH- or the xanthenyl anion X-, respectively, at first add to the carbonyl group of N-benzoylaziridines since high yields of benzoyl dihydroanthracene 3 or benzoyl xanthene 11 were obtained when in early stages the reaction was quenched with protons.The respective intermediate carbonyl adducts 2 and 10 had been considered to be precursors of products resulting from homolysis of the aziridine ring.It is now shown that quenching of the reaction between AH- or X- and N-benzoylaziridines 1a, b with methyl iodide or aroyl chlorides results in substantial yields of products derived from either AH- (or X-) or 1a,b.This indicates that 2 (or 10) are in equilibrium with AH- (or X-) and 1a, b.Study of the gegen ion influence with X- revealed that the equilibrium concentrations of 10-Na+ were much lower than those of 10-Li+ while simultaneously the ring opening of 1a was distinctly faster with X-Na+ than with X-Li+.This finding suggests that, contrary to the previous assumption, the equilibrium concentrations, of X- and 1a are responsibile for the (homolytic) ring opening.
