Daniel J. Emmerich

One‐Pot Synthesis of Pyrazole‐5(3)‐carboxyamides

Abstract A convenient one‐pot synthesis of eight pyrazole‐5(3)‐carboxyamides from the reaction of the 5(3)‐trichloromethylpyrazoles with amines, in good yield, is reported. These reactions show that the trichloromethyl group is a convenient precursor to carboxyamide groups.

Synthesis and crystal structure of (Z)-1-(phenylsulphenyl)-2-phenylethenyl p-toluenesulfonate

The reaction between 1-phenylsulphenyl-2-phenylethyne and p-toluenesulfonic acid in methylene chloride gives (Z)-1-(phenylsulphenyl)-2-phenylethenyl p-toluenesulfonate (1) in good yields. This reaction is both a regio- and a stereospecific cis addition, confirmed by X-ray crystal structure analysis of the title compound. 1 crystallizes in the monoclinic space group P21/n with the lattice parameters a = 10.556(3), b = 9.730(3), c = 19.687(3) Å, β = 105.05(2)°, V = 1952.7(8) Å3, and Z = 4. The results of elemental analysis, IR and NMR spectroscopy are included.

The effect of pressurized carbon dioxide on the cyclocondensation reaction between 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones and hydrazines

The synthesis of 1-unsubstituted and 1-phenyl-5-trifluoromethylpyrazoles from the reaction of 4alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)CH=C(R )OR, where R = Me, Et and R = H, Me, Ph] with hydrazines [NH2NHR , where R = H, Ph] in pressurized carbon dioxide is reported for the first time. Reaction conditions such as pressure, temperature and time were evaluated. The methodology developed herein was suitable to synthesize products in moderate to excellent yields (60 % 96 %) and short reaction times (15 45 min).

Haloacetylated enol ethers: 18

A convenient method for the synthesis of eight alkyl 6-[4,5-dihydroisoxazol-3-yl(-pyrazol-3(5)-yl)]hexanoates from the cyclocondensation of methyl 10,10,10-trifluoro[chloro]-9-oxo-7-methoxydec-7-enoates and hydroxylamine hydrochloride or hydrazine hydrochloride, respectively, in ethanol as solvent is reported. The reaction of methyl 10,10,10-trichloro-9-oxo-7-methoxydec-7-enoates with hydrazines furnished the pyrazole derivatives with the simultaneous transformation of trichloromethyl to carboxyl group.