2-Methylen-l-oxo

Die Addition von Dialkylaminen an cyclische a-Methylen-ketone (z. B. 2-Methylen-l-oxo-tetralin und 3-Methylen-2-oxo-bicyclo[2.2.1]heptan) kann an Aluminiumoxid als Kata-lysator durchgefuhrt werden4 ... 

Gras JL (1990) Methylene Ketones and Aldehydes by Simple, Direct Methylene Transfer 2-Methylene-l-oxo-l,2,3,4-tetrahydronaphthalene. In Organic Synthesis, Coll VII., p. 332. Wiley, New York, Chichester, Brisbane, Toronto, Singapore... 

METHYLENE KETONES AND ALDEHYDES BY SIMPLE, DIRECT METHYLENE TRANSFER 2-METHYLENE-l-OXO-l,2,3,4-TETRAHYDRONAPHTHALENE... 

This regioselectivity is practically not influenced by the nature of subsituent R. 3,5-Disubstituted isoxazolines are the sole or main products in [3 + 2] cycloaddition reactions of nitrile oxides with various monosubstituted ethylenes such as allylbenzene (99), methyl acrylate (105), acrylonitrile (105, 168), vinyl acetate (168) and diethyl vinylphosphonate (169). This is also the case for phenyl vinyl selenide (170), though subsequent oxidation—elimination leads to 3-substituted isoxazoles in a one-pot, two-step transformation. 1,1-Disubstituted ethylenes such as 2-methylene-1 -phenyl-1,3-butanedione, 2-methylene-1,3-diphenyl- 1,3-propa-nedione, 2-methylene-3-oxo-3-phenylpropanoates (171), 2-methylene-1,3-dichlo-ropropane, 2-methylenepropane-l,3-diol (172) and l,l-bis(diethoxyphosphoryl) ethylene (173) give the corresponding 3-R-5,5-disubstituted 4,5-dihydrooxazoles. 

Methylene-1-oxo-1,2,3,4-tetrahydro-naphthalene l(2//)-Naph-thalenone, 3,4-dihydro-2-methylene- (8,9) (13203-73-1) N-Methylanilinium trifluoroacetate Aniline, A-methyl-, trifluo-roacetate (8) Benzenamine, /V-methyl-, trifluoroacetate (9) (29885-95-8)... 

Keton + Cl — COOallyl) 6-Allyl-2-methyl-l-oxo- E18, 1048 (Keton + Cl-COOallyl) (Allyloxy-methylen)- E1S/1, 168 ( -CHN2 + Keton/R-OH) ( /Z)-2-(2-Butenyl)-l-oxo- E18, 1062 (Decarboxylier.)... 

Methylen-2-oxo- E17e, 510 (5-Methylen-1 -oxo-spiro[3.5] nonan + Li — CH2 — SeO —Ar) Spiro[4.5 dec-l-en 1-Methy 1-6-ox o-E17c, 2539f. (2-Cyclopropyl-methylen-l-oxo-cyclohexan/A) Spiro[4.5 dec-6-en l-Methyl-2-oxo-E17e, 510 [l-Oxo-spiro[3.5]non-... 

O —Si-enol + R-Cl) (WJts-4-tert.-Butyl-2-methyl-1-oxo-E13/2, 1380 (aus dem Hydrazon) 6-tert.-Butyl-2-methyi-l-oxo- E19c, 335 (O —Si-enol + R —Cl) (Butyloxy-methylen)- E15/1, 198 (3-NO — 2-oxo — 1,3-oxazolidin/ R-ONa)... 

Spiro 4.7]dodecan 4-Methylen-l-oxo- E17e, 506 [1-OR —2-methylen — 1-(CR2 — OSiR3) — Cyclobutan/H+)... 

Hydroxy-l -methy P2-oxo-3,5-diphenyI-l, 2-dihydio 3-Isobutyl-l-methyl-2-0X0-1,2-dihydio 3-IsopropyH-raethyl-2-oxo-l, 2-dihydio 3-Methoxy-l-methyl-2-0X0-1,2-[Pg.461]

Diphenyl-4-methoxycarbonyl-2-oxo- 2139 4-Ethoxycarbonyl-6-methyl-3-oxo- 2111 4-Methoxycarbonyl-3-methyl-2-oxo- 2139 4-Methylen-l-oxo- 2275... 

Zumeist werden Acceptor-substituierte Acetonitrile verwendet. Die erhaltenen Produkte liegen als 2-Methylen-4-oxo-l,3-thiazolidine vor. In vergleichbaren Fallen werden mit Carbonsaure-estern hohere Ausbeuten erhalten als bei Verwendung von Mercapto-essigsaure. 

Alkoxyall l Hydroperoxides. These compounds (1, X = OR , R = H) have been prepared by the ozonization of certain unsaturated compounds in alcohol solvents (10,125,126). 2-Methoxy-2-hydroperoxypropane [10027-74 ] (1, X = OR , R" = methyl), has been generated in methanol solution and spectral data obtained (127). A rapid exothermic decomposition upon concentration of this peroxide in a methylene chloride—methanol solution at 0°C has been reported (128). 2-Bromo-l-methoxy-l-methylethylhydroperoxide [98821-14-8]has been distilled (bp 60°C (bath temp.), 0.013 kPa) (129). Two cycHc alkoxyaLkyl hydroperoxides from cyclodecanone have been reported (1, where X = OR R, R = 5-oxo-l, 9-nonanediyl) with mp 94—95°C (R" = methyl) and mp 66—68°C (R" = ethyl) (130). Like other hydroperoxides, alkoxyaLkyl hydroperoxides can be acylated or alkylated (130,131). 

In the alternative approach.the 1,3-dipolar system can be constructed in several ways. Treatment of a-chloroacylhydrazones of diaryl ketones and certain aralkyl and dialkyl ketones (382) with NaH in anhydrous THF gives l-(disubstituted methylene)-3-oxo-l,2-diazetidinium inner salts (383). Reaction of (383) with DMAD in methylene chloride gave (384), a 2 1 adduct with loss of CO. Double bond migration in (384) occurred on heating to give (385). The intermediate in the cycloaddition was found to be (386), which on heating lost CO to form a new ylide system which in turn underwent reaction with more DMAD <81JA7743). 

Only one procedure has been reported recently within this category. Thus 7-chloro-l-methyl-5-phenyl-2,3-dihydro-lH-benzodiazepin-2-one 4-oxide (437) with dimethyl acetylenedicarboxylate in methylene chloride at 20° C for 3 days gave a separable mixmre of the primary tricyclic adduct, dimethyl lO-chloro-6-oxo-llb-phenyl-5,6,7, 1 lb-tetrahydroisoxazolo[2,3-t/] [ l,4]benzodiazepine-1,2-dicarboxylate (438), and its rearrangement product, 6-chloro-4-(2-methoxalyl-2-methoxycarbonyl-l-phenylvinyl)-l-methyl-3,4-dihydro-2(lT0-quinoxalinone (439) each product afforded 6-chloro-l-methyl-2(l//)-quinoxalinone (440) on refluxing in ethanol (see also Section 1.7.13). However, the final quinoxaline (440) was best obtained in 75% yield) by simply heating the initial substrate (437) and dimethyl... 

Chloro-2-[l,4-dimethyl(thiosemicarbazido)]quinoxaline 4-oxide (250) with dimethyl acetylenedicarboxylate gave 6-chloro-2-[A-(5-methoxycarbonyl-methylene-3-methyl-4-oxo-2-thioxoimidazolidin-l-yl)-A-methylammo]quinoxa-line 4-oxide (251) (EtOH, reflux, 5 h 54%) a homolog likewise." ... 

CN [2S-(2a,5a,6P)]-6-[[(hexahydro-l//-azepin-l-yl)methylene]amino]-3,3-dimethyl-7-oxo-4-thia-l-azabicyclo[3.2.0]heptane-2-carboxylic acid (2,2-dimethyl-l-oxopropoxy)methyl ester... 

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