2,4-Octadienal

Illustrative of the preparation of epoxyacetylenes are the reaction of perbenznio acid with 1 -ethyl-3-buten-1 -yne16 and of peracetic acid with 3>0-ditnethyl-2,4 Octadien-4-yne,10 as shown in Kqs. (8) and (9). 

C9H120 4-methyl-3-ethyl phenol 6161-67-7 20.338 139.820 2 17608 C9H16 7-methyl-2,4-octadiene 2216-70-8 15.810 166.083 1,2... 

Ebenfalls unter Stickstoff-Eliminierung und Fragmentierung des Substituenten in 2-Position wird durch Pyrolyse ausden Sulfoximiden oder Imino-phosphoranen (vgl. S. 842) von2-Amino-3-methyl-2H-indazol (Z,Z)-2,4-Octadien-6-in-sdure-nitrila s Hauptprodukt(neben Biphenylen und Dimethylsulfoxid bzw. Triphenylphosphan) gebildet (41 bzw. 32% Schmp. 15" Ol) ... 

Let us first understand the steric effect during the hydrogen shift in 6(5),2(E),-4 (Z)-2-deuterio-6-methyl-2,4-octadiene 15 that can exist as an equilibrium mixture of the conformers 15a and 15b (Scheme 2) [6]. The sigmatropic shift is suprafacial... 

Scheme 2 [l,5]-Hydrogen shift in 6(S),2( ),4(Z)-2-deuterio-6-methyl-2,4-octadiene... 

It can be formed during roasting by reaction of 2,4-octadienal with hydrogen sulfide, according to a mechanism proposed by Mottram (1991). 

Both structures in the center should lose C3H7 in the MS (see dashed lines). The top one doesn t fit the NMR though it should have 2 H s on the carbons attached to N. It also should show a strong IM - 15] + peak in the MS (loss of CH3), which is not seen, and it should give another Hofmann product 2,4-octadiene. The only possible correct structure therefore is... 

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