Diethyl chloromalonate

Reagent and conditions i, diethyl chloromalonate, DMF ii, DBN, MeOH iii, AcOH, H2O iv, AcONa, diethyl aminomalonate HCI, MeOH/H20 v, MeONa, MeOH vi, 2,5-dimethoxyTHF, 4-chloropyridine hydrochloride, dioxane vii, pyrrolidine viii, (a)POCI3, (b) 10%NaOH... 

The present procedure is applicable only to bromomalononitrile various a-halogen active methylene derivatives, (e.g., diethyl chloromalonate, methyl bromoacetoacetate) led predominantly to the formation of ring-contracted styrene derivatives. On the other hand, substituted cycloheptatrienylium salts with bromomalononitrile gave the desired dicyanoheptafulvene derivatives in excellent yields. One notable example is the synthesis of 5- and 7-(dicyanomethylene)-2,3-dihydrocyclohepta-1,4-dithiins.6... 

A heterogeneous mixture of diethyl chloromalonate (5 1.95 g, 10 mmol) and spray-dried KF (3.00 g, 50 mmol) in tetramethylene sulfone (30 mL) was stirred for 3h at 100-120°C, and then bcnzaldehyde (1.60 g, 15 mmol) was added to the mixture. After stirring for 10 h at 100 120 C, the mixture was poured into H20 and the product formed was extracted with Et20. After removal of the solvent, the residue was subjected to distillation yield 1.13 g (58%) bp 121-123 DC/8Torr. 

A new method for the preparation of diethyl thioxomalonate, already prepared from Bunte salts340 (Section m.E.5), has been introduced by Abelman351. In this approach, diethyl chloromalonate was reacted with cesium carbonate in the presence of elemental sulfur to yield the thioxoester which underwent a facile [4+2] cycloaddition (equation 74). 

Diethyl thioxomalonate, S=C(COOC2H5)2 (1). This reagent can be generated in situ from the Bunte salt (2) prepared by reaction of diethyl chloromalonate with sodium thiosulfate. 

Isoxazoline AT-oxides cannot be synthesized directly by the oxidation of 2-isoxazoline. Several methods to obtain 2-isoxazoline iV-oxide are discussed <9iHC(49)i>. The most commonly exploited route is by using nitroalkene, under a base promoted 0-alkylating condition. The reaction of nitro-alkene with diethyl chloromalonate afforded the 2-isoxazoline iV-oxide <91BSF562>. Dibromonitro... 

Diethyl chloromalonate and acetaldehyde give diethyl -chloro-<%-(l-hydroxy-ethyl)malonate analogously.695... 

A mixture of startg. thiosulfate monoester (prepared from diethyl chloromalonate and Na2S203) reacted with Et3N in the presence of startg. diene at 25-70° inter-... 

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