R. Martínez Alvarez

An improved modification of ritter reaction

The reaction of alcohols 1 with trifluoromethane-sulfonic anhydride (Tf2O) in dichloromethane in presence of a 2:1 excess of nitriles 3 affords the corresponding amides 5 in good yields.

An easy one-step synthesis of 4-alkoxypyrimidines from aliphatic esters and nitriles

Abstract The reaction of aliphatic esters with aliphatic or aromatic nitriles in the presence of trifluoromethanesulfonic anhydride affords substituted 4-alkoxypyrimidines in good yields. A mechanism of the investigated reaction is proposed.

Eine einfache methode zur darstellung tertiärer iodide

Abstract Hindered alkyl iodides may be prepared conveniently by treatment of the corresponding alcohols with magnesium iodide in n-pentane.

A new Procedure for the Synthesis of (E)-1-iodo-1-alkenes.

(E)-1-iodo-1-alkenes 4 can be prepared stereoselectively from aldehydes 1 via 1H-elimination of 1, 1-Di-iodoalkanes 3 with DBU.

Preparation of alkyl- and phenyl-substituted pyrimidines

Abstract Vinyltrifluoromethanesulfonates (triflates) which are obtained from the corresponding ketones, react in an excess of pure nitriles (acetonitrile, propionitrile, benzonitrile) at 80°C (20h) to form substituted pyrimidines 5 and 8 in good yields.

MASS SPECTRA OF IMPORTANT HETEROCYCLIC COMPOUNDS : CYCLOALKANE FUSED PYRIMIDINES

The electron impact mass spectra of several new cycloalkane-substituted pyrimidines are reported. The cleavage of the cycloalkanepyrimidines depends strongly on the alkyl ring size and on the substituents attached to this ring. The pyrimidines with fused small rings (cyclobutapyrimidines) undergo consecutive elimination of two nitrile molecules affording cyclobutadiene. However, for the pyrimidines with rings larger than cyclobutane, the main fragmentation observed involves ring opening with loss of alkyl radicals. The substituents with strong electronic effects attached to the alkyl ring promote a different cleavage mechanism with elimination of these groups. Copyright

Benzylic cleavage and McLafferty rearrangement under electron ionization conditions in the fragmentation of 5,6-dialkyl-2, 4-diarylpyrimidines

Several 5,6-dialkyl-2,4-diarylpyrimidines were prepared and their electron ionization (EI) mass spectra reported. The benzylic cleavage takes place easily together with an important McLafferty rearrangement. The involvement of the nitrogen atom appears to be important in the fragmentation of 5-methyl-substituted pyrimidines. In contrast, the 6-methyl-substituted pyrimidines undergo benzylic cleavage without hydrogen transfer. Thus, the difference in the mass spectrometric behaviour allows the identification of these isomeric compounds which, in contrast, exhibit only small differences in their NMR spectra. Copyright 1999 John Wiley & Sons, Ltd.

Selectivity in the reactions of less stable carbocations with magnesium halides in aprotic solvents. A theoretical approach to the constant selectivity principle

Abstract The solvolysis of 7,7-bis(trifluoromethylsulfonyloxy)-2-norbornene ( 1a ), 1-trifluoromethylsulfonyloxy-1-phenylethylene ( 2a ), 2-methyl-1-cyclohexen-1-yl triflate ( 3a ) and 4-camphenyl triflate ( 4a ) in carbon disulfide or diethyl ether with added MgI 2 and MgBr 2 yields a mixture of the corresponding halides 5b-e, 6b-c, 7b-c and 8b-c . The ionization of the triflate group is favoured by coordination with the magnesium halides. The reaction with MgI 2 was found to be second-order and is about 50 times more reactive than MgBr 2 . The selectivities of the intermediate cations 5–8 toward the nucleophiles MgI 2 and MgBr 2 are nearly constant, although the solvolysis rates differ by more than three powers of ten. A theoretical explanation of the constant selectivity principle is given.