Preparation of New Nitrogen-Bridged Heterocycles. XXXI. Cyclization Aptitudes of 2-Acylmethylthio-3-cyanoindolizines Having a Cyano or an Ester Group at the 1-Position.

Preparation of New Nitrogen-Bridged Heterocycles 72. A New Approach to 1-Acyl-3-(substituted methylthio)thieno[3',4':4,5]imidazo[1,5-a]pyridine Derivatives

“…The physical and spectral data of known compounds 3f, j and 4f, j were in accord with those described earlier by us 19) and Tominaga et al 15) and some data for the new compounds which were isolated are shown below. -c), (10a-c), and (12a-c).…”

First Ring Contraction-Desulfurization of 1-(Arylcarbonyl)pyrido[2,1-c]-1,4-thiazines to 1-(Arylcarbonyl)indolizines and Its Application to 3-Arylthieno[3,2-a]indolizine Synthesis

“…In particular, the largely shifted carbonyl absorption band (1611-1651 cm -1 ) appeared in the IR spectra of 7a-o are characteristic of the 2-acyl group in 5-membered heteroaromatic furans and thiophenes. 3,8,[10][11][12] In the 1 H-NMR spectra (Table 1) This large high field shift to the 4-Me group suggested the presence of the large shielding effect attributable to the 3-aryl group. The conformations of these molecules were confirmed finally by the Xray analysis of compound (7e).…”

“…CN>3-Ac>3-CO 2 Et>1-CO 2 Et), has been already established. 8,[10][11][12] Furthermore, the reactivity of the 1-ketone carbonyl group in 4a-f was expected to be higher than that of the 3-ester carbonyl one, because it is known that a ketone carbonyl group is generally more susceptible to a nucleophilic attack than a ester carbonyl one and that the reactivity of the 1-carbonyl group on diethyl 6,8-dimethylindolizine-1,3-dicarboxylate derivatives is increased strongly by the steric repulsion of the 8-methyl group. 7 When the deprotection of the 2-substituent of 4d-f, the removal of the ethyl acrylate generated, and the addition of (6) were not carried out because of their low yields (<5% Scheme 2…”

Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO)

“…[3][4][5] Particularly,t he development of oxidative functionalization of tertiary amines using molecular oxygen (O 2 )i sh ighly meaningful because traditional stoichiometric oxidants cause undesirable oxidation of sensitive functional groups in bioactive and natural compounds.A sac ontinuation of our interest in developing aerobic oxidative functionalization of tertiary amines, [6,7] we focused on methyl-selective a-oxygenation of tertiary amines.F ormamides,p roducts of a-methylselective oxygenation of N-methylamines,a re useful intermediates for transforming to versatile functional groups [8][9][10][11][12] and important building blocks for biologically active molecules. [13][14][15][16] Furthermore,d emethylation of N-methylamines can be realized via the deformylation of formamides. [17,18] Therefore,m ethyl-selective a-oxygenation would be ap ractical strategy for transforming N-methylamines to various value-added compounds.…”