Beitrag zum chemischen Verhalten der 4H‐1.3‐Oxazine

Abstract

Das Verhalten verschiedener 4 H-I .)-Oxazin-Derivate bei Hydrolyse. katalytischer Hydrierung und bei Reduktionsreaktionen wurde studiert. Die 2-standige Methylgruppe des 2.4.4.6-Tetramethyl-4 H-I .3-oxazins reagiert mit aromatischen Aldehyden in Gegenwart von Acetanhydrid zu 4.4.6-Trimethyl-2-styryl-4 H-1.3-oxazinen.

Optically active 4-aryl-4-trifluoromethyl-4H-1,3-oxa(thia)zines

“…We have found that compounds 1b, e, g, h are less reactive than N-3-oxoalkylamides [11,12] towards PCl 5 and produce S(À)-4-aryl-4-trifluoromethyl-4H-1,3-oxazines 2a-d (Table 2) only on 8 h boiling in benzene. The reaction is likely to involve the intermediate formation of imidoyl chlorides A which undergo intramolecular cyclization.…”

Cyclization of N-(3-Oxoalkyl)chloroacetamides Under Basic Conditions. Synthesis of cis-3,4-Epoxypiperidin-2-ones

“…90-91°C; d, 81 %, m.p. 104-105°C)— by reaction of the α,β-unsaturated ketones and chloroacetonitrile [ 6 ]; compound 1e (47%, b.p. 146-151°C/7 mm Hg)— by reaction of 2-methyl-1-propenyl (1,1,1-trimethylsilyl)ether with 1,3,5-trimethylhexahydro-1,3,5-triazene and ClCH 2 COCl, in the presence of TiCl 4 [ 7 ].…”

Synthesis of 5,6-Dihydropyridin-2(1H)-ones, 1,5,6,8,8a-Hexahydroisoquinolin-3(2H)-ones and 4a,5,6,7,8,8a-Hexahydroquinolin-2(1H)-ones by Intramolecular Wittig Reaction

“…90-91°C); 1b ( 81 %, m.p. 104-105°C) and anti - 1e (14%, m.p.156-157°C) were obtained from the α,β-unsaturated ketones and chloroacetonitrile [ 6 , 9 ]; compounds 1c ( 69%, m.p. 109-110°C) and anti - 1g (55%, m.p.…”

“…Although the Wittig reaction is widely used for the synthesis of heterocycles [ 4 ], the cyclization of N-(3-oxoalkyl)amides derivatives using this reaction has not been investigated until now. N-(3-Oxoalkyl)amides can be obtained by a number of synthetic methods [ 5 , 6 , 7 ], including diastero- and enantioselective ones [ 8 ], that makes them very promising precursors for the synthesis of 5,6-dihydropyridin-2(1H)-ones. The development of the methodology for pyrid-2-ones and the formation their hydrogenated derivatives formation led to our interest in this reaction [ 9 ].…”