Raymundo Cruz-Almanza

Efficient, intermolecular, oxidative radical alkylation of heteroaromatic systems under "tin-free" conditions.

Novel and efficient radical alkylation of several heterocyclic systems including pyrroles, indoles, furan and thiophenes is described using xanthate based radical chemistry. The present methodology could be used to provide rapid access to various nonsteroidal antiinflammatory drugs.

A tandem carbonylation/cyclization radical process of 1-(2-iodoethyl)indoles and pyrrole

Abstract The AIBN-induced radical reaction of 1-(2-iodoethyl)indoles and pyrroles with Bu 3 SnH under 80 atm of CO was examined. Carbon monoxide was efficiently trapped by an alkyl radical to form an acyl radical which underwent intramolecular addition to the aromatic system to produce bicyclic aromatic ketones after in situ oxidation.

A tandem radical addition/cyclization process of 1-(2-iodoethyl)indoles and methyl acrylate

Abstract Benzindolizidine systems are generated in moderate yields by a hexabutylditin mediated consecutive radical addition, cyclization, oxidation process from 1-(2-iodoethyl)indoles and methyl acrylate.

Anticoagulant and estrogenic effects of two new 17β-aminoestrogens, butolame [17β-(4-hydroxy-1-butylamino)-1, 3,5(10)-estratrien-3-ol] and pentolame [17β-(5-hydroxy-1-pentylamino)-1, 3,5(10)-estratrien-3-ol]

Abstract The syntheses and characterizations of two new 17β-aminoestrogens, butolame [17β-(4-hydroxy-1-butylamino)-1, 3,5(10)-estratrien-3-ol] and pentolame [17β-(5-hydroxy-1-pentylamino)-1,3,5(10)-estratrien-3-ol], are presented. Both compounds, when administered in single subcutaneous injections to male mice and rats, produce dose-dependent increases in blood clotting times that may last several days. The estrogenic effects assessed by the vaginal cornification test are of relatively short duration.

Intramolecular radical acylation of 2-methylsulfonylpyrroles

Abstract Primary alkyl radicals generated (AIBN/Bu 3 SnH) from 1-(2- or 3-haloalkyl)-2-methylsulfonylpyrroles are intercepted by CO (80 atm), and the acyl radicals so produced undergo intramolecular oxidative cyclization at the α-position, giving bicyclic ketones with retention or loss of the sulfonyl moiety.

Synthesis, characterization and X-ray structure of stannocanes substituted with a cyclic dithiophosphate ligand X(CH2CH2S)2SnnBu [S2P(OCH2C(Et2)CH2O)], (X=O, S): a study about the conformational tendencies and the relationship with the anomeric effect of the stannocane rings

Abstract The preparation and conformational study of two stannocanes, 5-n-butyl-5-(5′,5′-diethyl-2′-thioxo-1′,3′,2′-dioxaphosphorinane-2′-thiolate)-1-oxa-4,6-dithia-5-stannocane, O(CH2CH2S)2SnnBu[S2P(OCH2CEt2CH2O)] (1) and 2-n-butyl-5-(5′5′-diethyl-2′-thioxo-1′,3′,2′-dioxaphosphorinane-2-thiolate)-1,3,6-trithia-2-stannocane S(CH2CH2S)2SnnBu[S2P(OCH2CEt2CH2O)] (2) is reported. These compounds were prepared from the corresponding chloro-oxa and -thia-stannocanes and the sodium salt of dithiophosphoric acid (2-mercapto-2-thiono-1,3,2-dioxaphosphorinane) in ethanol. Compounds 1 and 2 were characterized by IR, EI-MS and multinuclear NMR (1H, 13C, 31P). The molecular structures were determined by X-ray analyses. The eight-membered ring in both compounds has a boat–chair conformation with a 1,5 transannular Sn⋯O (2.468 A), Sn⋯S (2.94 A) interaction. The 1,3,2-dioxaphosphorinane ring in 1 and 2 present a chair conformation with the stannocane in the axial position, in accordance with the anomeric effect. The coordination of the Sn-atoms is trigonal-bipyramidal in 1 and intermediate between trigonal-bipyramidal and a bicapped tetrahedral arrangement in 2.

Synthesis of 2H-1-Benzopyrans from Aryllithium and a,b-Unsaturated Aldehydes

The synthesis of 2,2-dialkyl-2H-1-benzopyrans (23), (25), (27), (30), (31) and (29) was performed employing the 1,2-addition reaction of aryllithium salts to cyclocitral, 3-methyl-2-butenal, citral and farne- sal respectively. Subsequent deprotection with a Mexican bentonitic earth (Tonsil) in wet acetone was followed by ring closure reaction as the key step. Interesting intermediate products were isolated in the formation of benzopyrans (30) and (31)

Oxidative radical cyclization on enamide systems using n-Bu3SnH and dilauroyl peroxide

Abstract Efficient 5- endo and 6- endo oxidative radical cyclizations on enamide systems are described using nBu 3 SnH and dilauroyl peroxide both as initiator and oxidant. Dibenzoyl peroxide and dicumyl peroxide were also tested in the same reaction and the product yields were very similar to those obtained with dilauroyl peroxide. The erythrina ring system was constructed in a two-step sequence featuring this novel process.

Synthesis of tricyclic-2-aminoindoles by intramolecular 1,3-dipolar cycloaddition of 1-ω-azidoalkylindoles

Abstract Thermolysis of the 1-ω-azidoalkylindoles 4 , bearing an electron attracting substituent at C-3 (CHO, COMe, COOMe, CN) provides imidazo[1,2- a ]indoles ( 5 , n =1), pyrimidino[1,2- a ]indoles ( 5 , n =2), and 1,3-diazepino[1,2- a ]indoles ( 5 , n =3).

Diastereoselective Alkylation of 1-Benzyl-(5S)-Substituted 2-Pyrrolidinones

Abstract The (S)-glutamic acid derivatives, (5S)-Methoxymethyl- and (5S)-Benzyloxymethyl-N-Benzyl-2-Pyrrolidinones, compounds 3a and 3b respectively, exhibit good to excellent diastereoselection upon alkylation with primary alkyl bromides or iodides.