98171-28-9

Upstream product

• 498-66-8 norborn-2-ene 
• 98171-26-7 6-Oxo-5-phenyl-6H-[1,3,4]oxadiazine-2-carboxylic acid methyl ester 
• 98171-27-8 (1α,4α,4aα,5β,8β,8aα)-4a,5,6,7,8,8a-Hexahydro-11-oxo-1-phenyl-4,1-(epoxymethano)-5,8-methanophthalazin-4(1H)-carbonsaeure-methylester 
• 611-73-4 Benzoylformic acid 
• 498-66-8 norbornene 

Downstream Products

• 98171-30-3 (1R^*,2S^*,3R^*,4S^*, α'S^*)-α-Oxo-α'-phenylbicyclo<2.2.1>heptan-diessigsaeure-dimethylester 
• 98171-32-5 Oxo-[(1S,2R,3S,4R)-3-((R)-10-oxo-9-phenyl-bicyclo[6.2.0]dec-1⁽⁸⁾-en-9-yl)-bicyclo[2.2.1]hept-2-yl]-acetic acid methyl ester 
• 98171-33-6 (1α,4α,4aβ,5α,8α,8aβ,9α,9aβ,10α,10aβ)-Dodecahydro-12-oxo-9-phenyl-10,9-(epoxymethano)-1,4:5,8-dimethanoanthracen-10(1H)-carbonsaeure-methylester 
• 98171-29-0 (1S,2R,6R,7R,8R)-3-Chloro-5-oxo-6-phenyl-4-oxa-tricyclo[6.2.1.0^2,7]undecane-3-carboxylic acid methyl ester 
• 140695-39-2 (4α,4aβ,5α,8α,8aβ)-1-Chloroctahydro-3-oxo-4-phenyl-5,8-methano-1H-benzopyran-1-carbonsaeure-methylester 
• 115410-85-0 (2Z,6Z)-5-Oxo-6-phenyl-4-oxa-bicyclo[6.2.1]undeca-2,6-diene-3-carboxylic acid methyl ester 
• 115410-94-1 C₁₈H₁₈O₄ 

Relevant academic research and scientific papers

Cycloadditions of 6H-1,3,4-oxadiazin-6-ones (4,5-diaza-α-pyrones). Part 16. 4-Substituted and 4,5-disubstituted methyl 3-phenyl-α-pyrone-6-carboxylates from γ-oxoketenes via α,δ-dibromo-δ-lactones

The addition of bromine to the γ-oxoketenes 4, 10 and 22 and the elimination of two equivalents of hydrogen bromide from the resulting α,δ-dibromo-δ-lactones 5, 12 and 23 to give the α-pyrones 7, 19 and 20, respectively, are described. Since the isolation of neither 4, 10 and 22 nor 5, 12 and 23 proved necessary, the α-pyrones have been prepared in one-pot procedures from methyl 6-oxo-5-phenyl-6H-1,3,4-oxadiazine-2-carboxylate 6.

Cycloadditions of 6H-1,3,4-Oxadiazin-6-ones (4,5-Diaza-α-pyrones), 12. - Dieckmann Condensations without Bases

Prepared by treatment of methyl 6-oxo-5-phenyl-6H-1,3,4-oxadiazine-2-carboxylate (1) with norbornene, norbornadiene, and styrene, respectively, the γ-oxoketenes 2, 5, and 7 were allowed to react with methanol.Inter alia, the semiacetals 3, 6, and 10 of 1,2-cyclopentanedione derivatives were formed.The identity of 3 has been established by an X-ray structure analysis.The pathway to these compounds seems to be closely related to the mechanism of the Dieckmann condensation.By using methanol, it has been shown that the semiacetal methoxy group underwent an intramolecular migration.Methanol was eliminated from semiacetal 10 by chromatography on silica gel with formation of the enol 11.In addition to 3 and 10, the dimethyl adipates 4 and 9 were observed as the expected methanolysis products of the γ-oxoketenes 2 and 7, respectively.The diesters 9 were obtained on a second route from 7.Treatment of 7 with trifluoroacetic acid and subsequent hydrolysis gave rise to the monoesters 12, which were converted into the diesters 9 by conventional esterification. Key Words: 1,3,4-Oxadiazine-2-carboxylate, methyl 6-oxo-5-phenyl- / Diels-Alder reactions / Ketenes, γ-oxo- / 1,2-Cyclopentanedione derivatives / Adipic acid, substituted 2-oxo- dimethyl esters

Cycloadditions of 6H-1,3,4-Oxadiazin-6-ones (4,5-Diaza-α-pyrones), 11. - δ-Chloro δ-Lactones from γ-Oxo Ketenes

Prepared from 1,3,4-oxadiazinone 1 with norbornene, cyclopentene, cyclopentadiene, and indene, the γ-oxo ketenes 2, 5, 6, and 7 have been converted into the δ-chloro δ-lactones 3, 8, 9, and 10, respectively, by treatment with hydrogen chloride.The configu

Cycloadditions of 1,3,4-Oxadiazin-6-ones (4,5-Diaza-α-pyrones), 9. - Methyl 6-Oxo-5-phenyl-1,3,4-oxadiazin-2-carboxylate - Synthesis and Reactions with Norbornene, Norbornadiene, Cyclopropenes, Cyclobutene, and Benzvalene

Methyl 6-oxo-5-phenyl-1,3,4-oxadiazin-2-carboxylate (7) was prepared by treatment of hydrazone 6 with dicyclohexylcarbodiimide.The reactions of 7 with norbornene and norbornadiene afforded the Diels-Alder adducts 8 and 9, respectively, which decomposed in solution at 20 deg C to give mainly the γ-oxoketenes 10 and 12 and small amounts of the β-lactones 11 and 13, respectively.The stable γ-oxoketenes 10, 12, and the bis(γ-oxoketene) 14 were obtained directly from solutions of 7 and the respective olefin.Cyclopropene, 1-methylcyclopropene, and cyclobutene were converted by 7 mainly into the oxepin derivatives 15, 17, 18, and the oxocin derivative 19, respectively.Benzvalene and 7 provided the tetracyclo2,8.04,6>octanone 21.In these reactions, small quantities of β-lactones were formed, too, which together with the β-lactones 11 and 13 give evidence for the dihydropyryliumolates 24 as intermediates in the thermal denitrogenation of the Diels-Alder adducts of 7, e.g. 8 and 9.

INTRAMOLEKULARE -CYCLOADDITIONEN VON γ-OXOKETENEN

The γ-oxoketenes, which are accessible from methyl 1,3,4-oxadiazin-6-one-2-carboxylate 1 and cycloalkenes, are shown to undergo an intramolecular cycloaddition either on heating or on photolysis to give different stereoisomers of β-lactones of the 3-oxo-2-oxa-bicyclohexane-type.