Ethyl 1-propynyl

Allenyl methyl sulfoxide, 213 - (2) Methyl 1,2-pentadienyl sulfoxide, 213 - (3) Ethyl 1-propynyl sulfoxide, 214 - (4) Ethyl 1--propynyl sulfone, 214 - (5) Allenyl methyl sulfone, 215... 

In order to study the mechanism of the furan formation, the following reactions were carried out. The reaction of isomeric 2-butynyl methyl carbonate (160) and 1-m ethyl propynyl methyl carbonate (161) with methyl acetoacetate (162) gives the same product 163. This shows that the furan formation from 160 and 161 proceeds via a common intermediate. 

Better results were observed when HMPA was used as a cosolvent11. One equivalent of lithium diisopropylamide (1 M in THF) was used to deprotonate 5 at — 78 °C. The electrophile (ethyl iodide, allyl bromide and 2-propynyl bromide, 1.1 equiv) was dissolved in HMPA (1.2equiv) and added at — 40 °C. 

Di(3-metliylpentynyl)-3 poroxide or Bi ( 1-methyl- l-ethyl-2-propynyl)-peroxide. 

In many compounds R3 and R4 have been the same, the commonest substituent being methyl,53"10,13,15 17 although examples having ethyl,6,15 2-cyanoethyl,7 2-propenyI,7,11,13 2-propynyI,13 benzyl,7,13 and phenyl15 are also known. Where R3 and R4 are different, R3 has generally been methyl, and exceptionally trideuteriomethyl,18 or ethyl,12,13 whereas R4 has been ethyl,18 2-propenyl,7,13,18 3-methyl-2-butenyl,12,13 2-propynyl,13,18 or benzyl.7,10,13,18... 

Dimethyl-4//-pyrazoles, bearing a 2-propenyl or a 2-propynyl group in the 4-position, rearrange by [3,3]-sigmatropic processes.11 13 If a 4-methyl or 4-ethyl substituent is also present (80 R = H or Me), two competing pathways are observed (Scheme 20). 

The preparation of unsubstituted 2//-thiopyran (6, up to 82%) from 3-propynyl vinyl sulfide seems to be the simplest example.21,23 Similarly, homologs 101a,21 cyanides 101b,146 ketones 101c,141 and ethyl esters lOld148 were prepared in satisfactory yields. The same approach was subsequently explored for the synthesis of 15 and similar condensed systems21,43,137 (see also 5,5-dioxides in Section V,G,3). 

Liq, bp 60° at 76 mm b ( 1-methyl-l-ethyl-2-propynyl)peroxide or di-(3-methyl-pentyny )-3-peroxide,... 

Mono- and di-alkylated furans were synthesized in a one-pot preparation from 2-propynyl-2-tetrahydropyranyl ether (106), butyllithium and formaldehyde. The intermediate allenyl ether (107) presumably cyclizes via a 2-(2-tetrapyranyloxy)-2,5-dihydrofuran (108) to afford the heterocycle (109) (79AG(E)875). In a similar manner, singly and doubly branched tetrahydropyranyloxybutynolates afforded the substituted furans (110) (Scheme 20). The thermocatalytic isomerization of ethyl l-methyl-2-phenylcyclopropene-3-carboxylate yielded the furan, possibly by a 1,3-sigmatropic displacement step or by a non-concerted biradical intermediate (75T2495). 

Propynyl Vinyl Sulfide (or Propargyl vinyl sulfide). HC = C.CH2.S.CH CH2 mw 98.17 colorl liq bp 28° at 10mm RI 1.5183. Sol in pentane. Prepn is by reacting Na ethyl vinyl sulfide with propynyl bromide in pentane at 0° and then dstlg off the pentane solvent under vac at 20—25°. The residual is then redistld to remove the sulfide at 28°/10mm. The yield is 88—93%. Expl decompn occurs above 80° Refs 1) Beil, not found 2) L. Brandsma, Preparative Acetylenic Chemistry , Elsevier, NY (1971), 7 181... 

Bis( 1,1-dimethyl-2-propynyl)-peroxide. See under Acetylene Hydroperoxides A66-R Bis(hydroxylamino) Azide A525-L Bi s (hvdroxym ethyl )methyl aminomethane. See Aminomethylpropanediol A232-R 4-[Bi s(p-hydroxyphenyl)m ethylene]- 2,5-... 

Alkylation, of 2-acetamidothiazoles, 35, 37 with alkali amides, 34, 35 of alkylaminothiazole, 34 with alcohols, 47, 80, 90 of aminothiazoles, with alcohols, 38 with benzyl chloride. 33 with chloracetic acid, 33 with chloracetic esters, 33 with 3-chloropropionic acid, 33 with dimethylaminoethylchloride, 35 with ethylene oxide, 34, 38 with ethyl iodide, 33 with phenethyl chloride, 35 with 2-propynyl bromide. 32 in aprotic solvents, 35 of azothiazoles, 105... 

Phenyl(propynyl)iodonium tetrafluoroborate reacts with potassium 2-phenyl-1,3-indandionate in tetrahydrofuran to give the alkynyl and spiroannulated indandiones shown in equation 265. With sodium 2-ethyl-1,3-indandionate in terf-butyl alcohol, a vinyl ether is produced (equation 266). These observations are relevant to the general comments in section II.D.7 concerning the fate of 26 and related alkylidenecarbenes in reactions of [5 + OJenolates with alkyliodonium ions containing short (< three carbons) alkyl chains. 

Dimetbyl-l, 2-tellurazole1 1.7 g (15 mmol) of hydroxylamine O-sulfonic acid are dissolved in 5 ml of water, the solution is cooled to 0°, and 1.23 g (15 mmol) of methyl propynyl ketone are added to the vigorously stirred solution under nitrogen. The solution is stirred for 35 min and 2.5 g (30 mmol) of sodium acetate and 25 ml (l 5 mmol) of a 0.6 molar aqueous solution of potassium telluride are added to the solution over 20 min. The resultant solution is allowed to warm to 20 and is then stirred for 4 h. The reaction mixture is extracted 4 times with 20 ml portions of ethyl acetate and the extract is dried with anhydrous sodium sulfate, filtered, and evaporated to dryness. The residue is sublimed at 70°/0.001 torr and the sublimate recrystallized from acetone yield 0.3 mmol (10%) m.p. 111 . 

Preparation of 2-(lH-imidazo[4,5-c]quinolin-l-yl)ethyl (2-propynyl) ether... 

The mass spectrometric evidence on the hydride-ion transfer from C3H8 to methyl, ethyl and vinyl ions has been discussed vide supra). A careful quantitative study (Bone e al., 1967) showed that the hydride ion abstraction (29) represents indeed the predominant reaction of propynyl ions in propane, being four to ten times faster than any competing process. The hydride-ion transfer (33), which causes the formation of C3H7T, is observed in the mass spectrometer (Derwish et al., 1964b Bone et al., 1967 Munson et al., 1964), as well as the transfer from CsHs to the C2HI and 03 ions, that represents the source of ethane and propylene, according to Eqs. 30 and 32. 

The [2 + 2] cycloaddition of the propynyl tungsten complex (12b) has been found to be stereospecific with the cis and trans isomers of eAyl prc nyl ether." ITie reaction with c/s-propenyl ethyl ether gave rise to the cyclobutenyl complex (18), in addition to a minor amount of the ring-opened dienyl carbene complex (19). The stereochemistry about the double bonds in the dienyl complex (19) revealed that it was derived from a thermal electrocyclic conrotatory ring opening of the c/s-cyclobutenyl carbene complex (18) and thus the stereochemistry is completely retained in this cycloadditirxi. In support of this analysis it was found that cyclobutenyl complex (18) could be thermally opened to the dienyl complex by heating in an inert solvent at 50 C. In the cycloaddition of the propynyl complex (12) with trans-... 

---