54580-22-2

Upstream product

• 1000-87-9 2,4-dimethyl-2,3-pentadiene 
• 1133-23-9 1,2-di-isopropylidene-3,3,4,4-tetramethylcyclobutane 
• 107464-95-9 1-(2,4-dimethylpent-1-en-3-ylidene)-2,2,3,3-tetramethylcyclopropane 
• 94526-06-4 1-isopropylidene-2,2,4,4,5,5-hexamethylspiropentane 
• 114522-88-2 1-(2-hydroxy-2,4-dimethylpent-3-ylidene)-2,2,3,3-tetramethyl-cyclopropane 
• 69856-67-3 3,3,3',3',5,5,5',5'-octamethyl-3,3',5,5'-tetrahydro-4,4'-bi(4H-pyrazolylidene) 
• 94526-05-3 2,2,2',2',4,4,4',4'-octamethyl-3,3'-bithietanylidene 1,1,1',1'-tetraoxide 
• 58721-02-1 2,2,4,4-tetramethylthietan-3-one 1,1-dioxide 
• 94525-98-1 (2,2,4,4-Tetramethyl-1,1-dioxo-1λ⁶-thietan-3-ylidene)-hydrazine 
• 94526-02-0 3-diazo-2,2,4,4-tetramethylthietane 1,1-dioxide 
• 94526-04-2 2,2,2'',2'',4,4,4'',4''-octamethylthiirane-2',3'-dispiro-3,3''-bis(thietane) 1,1,1'',1''-tetraoxide 
• 94526-03-1 2,2,2'',2'',4,4,4'',4''-octamethyl-2',5'-dihydro<1,3,4>thiadiazole-2',5'-dispiro-3,3''-bis(thietane) 1,1,1'',1''-tetraoxide 
• 19547-10-5 ethyl α-diazoiso-propylacetate 
• 107464-94-8 1-(1-ethoxycarbonyl-2-methylpropylidene)-2,2,3,3-tetramethyl-cyclopropane 

Downstream Products

• 527-84-4 2-methylisopropylbenzene 
• 106-42-3 para-xylene 
• 54580-23-3 3,4-Diisopropyl-2,5-dimethyl-2,4-hexadien 

Relevant academic research and scientific papers

THE GENERATION AND SIGMATROPIC REARRANGEMENT OF A DERIVATIVE OF VINYL-TMM (2,5-DIMETHYL-3-ISOPROPYL-4-ISOPROPYLIDENEHEX-2-EN-1,5-DIYL)

The thermal rearrangement of 2,5-dimethyl-3-isopropyl-4-isopropylidenehex-2-en-1,5-diyl to 4-isopropyl-3-isopropylidene-2,5-dimethylhexa-1,4-diene involves a 1,6-sigmatropic shift of hydrogen which may occur in antarafacial manner.

Use of the Diazoalkane-thione Reaction in the Synthesis of a Vinyltrimethylenemethane Precursor

Previous studies have shown that the reaction of diazoalkanes with 3,5-dihydro-3,3,5,5-tetramethylpyrazole-4-thione (6) provide a flexible route for the synthesis of precursors to trimethylenemethane (TMM) (1) and tetramethylene-ethane (TME) (2) biradicals.We now show that this route can be adapted for the synthesis of a precursor to another type of non-Kekule polyene, a vinyl-TMM biradical (3).The thermal isomerisation of 1-(2,4-dimethylpent-1-en-3-ylidene)-2,2,3,3-tetramethylcyclopropane (27) to 4-isopropyl-3-isopropylidene-2,5-dimethylhexa-1,4-diene (11) which involves a vinyl-TMM intermediate (3-isopropyl-4-isopropylidene-2,5-dimethylhex-2-ene-1,5-diyl) was shown by deuterium labelling to involve a 1,6-hydrogen shift.It is suggested that such sigmatropic rearrangements of non-Kekule polyenes may involve orbital symmetry control.Related examples are discussed.Two reactions discovered incidentally in the course of this work are of some interest, one involving the synthesis of an allylic amine through the thermal rearrangement of an aziridine (2-isopropyl-3,3-aziridine) (16) and the other the formation of an oxathiole (20) through the reaction of a thione (6) and an α-diazo ketone (3-diazo-4-methylpentan-2-one) (18).

Preparation, Pyrolysis, and Photolysis of Three Sterically Crowded Alkenes, 3,3,3',3',5,5,5',5'-Octamethyl-3,3',5,5'-tetrahydro-4,4'-bi(4H-pyrazolylidene) 2,2,4,4-Tetramethyl-3-(3,3,5,5-tetramethyl-3,5-dihydro-4H-pyrazol-4-ylidene)-thietane 1,1-Dioxide and 2,2,2',2',4,4,4',4'-Octameth...

Photolysis and pyrolysis of the title compounds involve a stepwise elimination of nitrogen and/or sulphur dioxide and reactions which can be interpreted in terms of a series of trimethylenemethane (TMM) biradical intermediates.However, the photosensitised photolysis of the bi(pyrazolylidene) (11) give products indicative of an elimination of both nitrogens and the generation of a tetramethylene-ethane (TME) biradical intermediate.New synthesis of a number of highly sterically crowded alkenes including 2,2,4,4-tetramethyl-3-(3,3,5,5-tetramethyl-3,4-dihydro-4H-pyrazol-4-ylidene)thietane 1,1-dioxide (12) and 2,2,2',2',4,4,4',4'-octamethyl-3,3'-bithietanylidene 1,1,1',1'-tetraoxide (13), are described.Flash vacuum pyrolysis (f.v.p) of 3,3,3',3',5,5,5',5'-octamethyl-3,3'-5,5'-tetrahydro-4,4'-bi(4H-pyrazolylidene) (11) at 400 deg C gives 3,3,5,5-tetramethyl-4-(2,2,3,3-tetramethylcyclopropylidene)-3,5-dihydro-4H-pyrazole (21), at ca. 400 deg C 1-isopropylidene-2,2,4,4,5,5-hexamethylspiropentane (22), and at ca. 580 deg C a ca. 5:1 mixture of 4-isopropyl-3-isopropylidene-2,5-dimethylhexa-1,4-diene (23) and 2-(2,3-dimethylbut-1-en-3-yl)-1-isopropyl-3,3-dimethylcyclopropene (27).Above 700 deg C a complex mixture of aromatic products and low molecular weight hydrocarbons is produced which includes ethane, ethylene, propene, isobutane, and isobutene, p-xylene, o-cumene and probably m-cumene, and 2,5-dimethylisopropylbenzene.F.v.p. of the dihydropyrazole sulphone (12) gives initially 2,2,4,4-tetramethyl-3-(2,2,3,3,-tetramethylcyclopropylidene)thietane 1,1-dioxide (41) and at higher temperatures similar mixtures to those obtained from the bipyrazolylidene (11).Similar results were also obtained for the f.v.p. of the bis-sulphone (13).Photolysis of the bipyrazolylidene (11) gave initially the dihydropyrazole (21) and then a 48:52 mixture of the spiro compound (22) and 2,2,2',2',3,3,3',3'-octamethylbicyclopropylidene (42).Photolysis of the dihydropyrazole sulphone (12) gave 2,2,4,4-tetramethyl-3-(2,2,3,3-tetramethylcyclopropylidene)thietane 1,1-dioxide (41).Benzophenone-sensitised photolysis of the bipyrazolylidene (11) gave 1,2-di-isopropylidene-3,3,4,4-tetramethylcyclobutane (32).