Condensation of methyl 2-chloro-3-(3-nitrophenyl)-2,3-epoxypropionate with 1,2-phenylene diamine

It is established that the -chloroepoxide methyl 2-chloro-3-(3-nitrophenyl)-2, 3-epoxypropionate, in contrast to its a-chloroketone isomer methyl 3-(3-nitrophenyl-3-chloro-2-oxopropionate, forms 2-(3-nitrophenyl-3methoxycarbonylquinoxaline in reaction with 1,2-phenylene diamine, whereas the condensation of the achloroketone with 1,2 phenylene diamine gives 3-(-chloro-3-nitrophenyl)-2-oxo-1,2-dihydroquinoxaline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1105-1108, August, 1994.     

2,3-O-Isopropyliden-L-Sorbofuranose (MIPSF) und 2,3; 4,6-Di-O-Isopropyliden-L-Sorbofuranose (DIPSF)

Ohne Zusammenfassung     

Structural isomers of 2-(2,3 and 4-substituted-phenyl)-1,2-benzisoselenazol-3(2H)-one: A Theoretical Study

A series of 2-(2,3 and 4-substituted-phenyl)-1,2-benzisoselenazol-3(2H)-one molecules were theoretically investigated by the use of density functional theory (DFT) calculations at the B3LYP/6-311++G^∗∗ level of the theory. The substituents studied in this work are X = H; CH₃; NH₂; OH; OCH₃; F, Cl; Br; NO₂; CN; COCH₃; CO₂H; CO₂Me; SH; BH₂. We have selected these functional groups to be placed in the 2, 3 and 4 positions with relation to the benzisoselenazol moiety in order to show the effect of these structural modifications on the electronic properties of the molecules.     

Hydroborierung von 3-methyl-1,3-butadien mit 1,2:1,2-bis(tetramethylen)diboran(6)

The nature of the hydroboration product obtained from 3-methyl-1,3-butadiene and 1,2 : 1,2-bis(tetramethylene)diborane(6) (1) allows for the discussion of the reaction mechanism. The hydroboration proceedsby retention of the cyclic structure in the first step, followed by exchange of BH and BC bonds and final cyclic hydroboration to give 1-(boracyclopentyl)-4-(3-methylboracyclopentyl)butane (5). The structural assignment of 5 is based on ¹H, ¹¹B and ¹³C NMR data.     

Syntheses of 3-substituted 2,3-dihydrobenzofuranes, 1,2-dihydronaphtho(2,1-b)furanes,and 2,3-dihydro-1H-indoles by tandem ring closure-S(RN)1 reactions

3-Substituted 2,3-dihydrobenzofuranes (7a-c), 1,2-dihydronaphtho(2,1-b)furanes (10a-c), and N-substituted 2,3-dihydro-1H-indoles (8a-c, 9a,b) are obtained in very good yields by S(RN)1 photostimulated reactions in liquid ammonia from adequate haloaromatic compounds ortho-substituted with a suitable double bond (3a,b; 4a,b; 5a; 6a,b) and Me3Sn-, Ph2P-, and -CH2NO2 anions. The novelty of the work involves the versatile application of a 5-exo ring closure process during the propagation cycle of the S(RN)1 reaction; the alkyl radical intermediates formed react with the nucleophiles to afford the ring closure-substituted heterocycles. The factors governing the observed product distribution are discussed.