4- ethoxy-l-

The need for pyrazoles substituted with the trifluoroacetyl group led to the reaction of ethoxyvinyl ether with trifluoroacetic anhydride, yielding 4-ethoxy-l,l,l-trifluoro-3-buten-2-one (38) this further reacted with aldehyde / fZ-butyUiydrazones, and after cyclization at room temperature under mildly acidic conditions the pyrazoles were obtained in satisfactory yields (eq. 7). Further treatment with H2SO4 removed the tert-huty group, thus providing an opportunity for further derivatization at N. ... 

Alkyl 4-Ethoxy-l-naphthyl Carbonate Formation/Cleavage ... 

This group was developed for the protection of amino acids. It is formed from 4-ethoxy-l,l,l-trifluoro-3-buten-2-one in aqueous sodium hydroxide (70-94% yield). Primary amino acids form the Z-enamines, whereas secondary amines such as proline form the -enamines. Deprotection is achieved with 1-6 N aqueous HCl in dioxane at rt. ... 

Allylic bromination, with A -bromosuccinimide (NBS), of 4-ethoxy-l,2-dihydrocyclo-pent[rf]azepine (8), formed by ethylation (with Meerwein s reagent) of the corresponding 4-oxo derivative, followed by in situ dehydrobromination of the resulting bromo compound with basic alumina, produces a low yield of l-bromo-2-ethoxycyclopent[c/]azepine (9) as a photosensitive, sapphire-blue, crystalline solid.55... 

The cyclopropane derivative 1, formed by the addition of dibromocarbene to 4-ethoxy-l-tosyl-1,2-dihydroquinoline, in refluxing pyridine undergoes ring expansion and aromatization to the 1/f-l-benzazepine 2.168... 

The crystal structure of the mesogenic 4-(3"-pentenyl)-4 -(ethoxy)-l,l -bicyclohexane (PEBCH) was determined by Nath et al. [78]. This compound exhibits a nematic phase. The molecules are packed parallel to each other in an imbricated mode. 

Condensation of ethylenediamine with 4-ethoxy-l, 1,1 -trifluoro-3-buten-2-one occurs readily to give the simple 2,3-dihydro-l//-l, 4-diazepine 92 in good yield <00SC677>. 

Kormachev, V.V. and Mitrasov, Y.N., Reaction of phosphorus pentachloride with 4-ethoxy-l-butene, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 24, 1570, 1981. 

The 2-phenyl derivative of 4-ethoxy-l-ethylpyrimidinium tetrafluoro-borate undergoes with liquid ammonia deethylation at N-1 as well as deethoxylation at C-4, a mixture of 4-ethoxy-2-phenylpyrimidine (18) and l-ethyl-4-imino-2-phenylpyrimidine (19), respectively, being obtained (Scheme IIL12) (77RTC183). 

Reaction of 4,6-diethoxy-l-ethylpyrimidinium tetrafluoroborate (21) showed similar behavior no N-deethylation, but deethoxylation at position 4 as well as at position 6 was observed, as indicated by the formation of the two isomeric products l,4-dihydro-6-ethoxy-l-ethyl-4-iminopyrimidine hydrogen tetrafluoroborate (23) and l,6-dihydro-4-ethoxy-l-ethyl-6-... 

Compounds containing an a-aminoimidate fragment (HN=C-C-NH2) as in ethyl 2-amino-2-oxoethanimidoate 30 and 2-aminoethanimidamide 31 reacted with sulfur monochloride to give, respectively, 4-ethoxy-l,2,5-thiadiazol-3-ol (32) and 3-amino-l,2,5-thiadiazol (33) (1967JCX72823 Scheme 16). Yields were moderate. 

An activated 4-alkylidene-2-ethoxyoxetane reacted smoothly with acetone at —30°C to give 6-alkylidene-4-ethoxy-l,3-dioxane in 92% yield (Equation 95) <2003JA14446>. 

The 4-ethoxy-l-naphthyloxycarbonyl group is a valuable electrochemically labile protecting group for alcohols and amines. The deprotection of bomeol 105 and gerani-... 

Ct-Ethoxy styrene-vinyl ethyl ether 1, l,4-Trimethoxy-4-ethoxy-l-phenylbutane (45%) ... 

Diphenyl-4-ethoxy-l-tellurinium fluorosulfate reacted with 2,2-dimethyl-4,6-dioxo-1,3-dioxane (Meldrum s acid) to give 4-(2,2-dimethyl-4,6-dioxo-l, 3-dioxane-5-ylidene)-... 

Pofy-l-vinyluradl (poly-VUr, 10) was also obtained by a free-radical polymerization6). In this case, it should be noted that the formation of substituted dihydrouradl rings occurred via a cydopolymerization mechanism11). y-Ray induced solid-state polymerization of the monomer (9) in high concentration and at low temperature excluded cydopolymerization completely12). Poly-VUr was also prepared by a free-radical polymerization of 2-ethoxy-4-l-vinyl-pyrimidone (ii)8) or 4-ethoxy-l-vinyl-2-pyrimidone (13)iy> followed by acid hydrolysis of the resulting polymers (12) or (14) (Scheme 2). 

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