Sergio Cossu

Lymphangioma-like variant of Kaposi's sarcoma: clinicopathologic study of seven cases with review of the literature.

The clinical and pathological features of seven cases of lymphangioma-like Kaposis sarcoma (KS) are reported. As with the other subtypes of KS, the lymphangioma-like variant occurs more often in men aged 59-80 years. Clinically, the lesion appears intermingled with the classical forms of KS, but a bulla-like appearance recognized in seven of 13 cases has been considered as a clinical hallmark of this variant. Although occasional cases have shown aggressive behavior, the most frequent clinical course is slowly progressive with localized or diffuse involvement of lower limbs. The histological pattern, characterized by permeation of dermal collagen by labyrinthine vascular channels lined by a flattened endothelium, must be differentiated from spindle cell hemangioendothelioma, low-grade angiosarcoma, targetoid hemosiderotic hemangioma, and benign lymphangioendothelioma.

Optically active 4-oxaroline derivatives: New useful chiral synthons derived from serine and threonine

Abstract A very simple procedure for the preparation of chiral optically active N-protected-4-carboxy-1,3-oxazolidine (4-oxaproline) derivatives starting from serine and threonine is described which avoids the use of toxic solvents or reagents. Elaboration of these compounds allows significant improvement in the handling of serine and threonine during the multigram preparation of oligopeptide structures and affords versatile chiral building blocks for the organic synthesis.

Synthesis of 1,1′-Dibenzo- and 1,1′-Dinaphtho-2,2′-Dithiols from the Respective Thiophenes

Abstract The title compounds 1 and 2 were prepared from the respective, inexpensive and readily available thiophenes via reaction with lithium and sulfur monochloride, followed by reduction with lithium aluminium hydride.

Unusual reactivity of 4-carboxyamido-2-oxazoline systems: new synthesis of optically active n-sulphonyl derivatives.

Abstract Optically active 2-alkyl-2-oxazoline-4-carboxyamides, derived from enantiomeric pure α-amino-β-hydroxy acids, react with aryl- and alkyl sulphonyl chlorides in pyridine affording the corresponding optically active 2-alkyl-2-oxazoline-4-carboxyamido- N -sulphonyl derivatives without appreciable racemization.

Generation and rearrangement of C2-symmetric chiral allyl anions derived from dibenzo- and 1,1'-dinaphtho-2,2-'dithiopropenes

Abstract The allyl anions generated from 4 H -dinaphtho[2,1- f :1′,2′- h ][1,5]dithionin ( 6 ) and 2-ethenyl-dinaphtho[2,1- d :1′,2′- f ][1, ( 8 ) rearranged both to the thiolate 10 which further reacted with water or methyl iodide to afford 9 or 12 respectively. A similar behavior was exhibited by the anion of 4 H -dibenzo[ f,h ][1,5]dithionin ( 15 ).

Synthetic equivalents to substituted acetylenes in cycloaddition reactions. Dienophilic reactivity of 2-methyl-, 2-phenyl- and 2,3-trimethylene-1,4-benzodithiins-1,4-tetroxides

Abstract Dienophiles 2-methyl-1,4-benzodithiin-1,4-tetroxide (3a), 2-phenyl-1,4-benzodithiin-1,4-tetroxide (3b) and 2,3-trimethylene-1,4-benzodithiin-1,4-tetroxide (3c) have been prepared with different methods starting from benzene-1,2-dithiol (1). Their reactivity was tested towards cyclopentadiene, sulfolene, furan and 1,3-cyclohexadiene. The Diels-Alder adducts to cyclopentadiene were converted into the corresponding unsaturated hydrocarbons, mimicking the Diels-Alder reaction of substituted acetylenes. The X-ray structure determinations of 4b, a secondary product in the preparation of 2-phenyl-1,4-benzodithiin-1,4-tetroxide and of the adduct of the phenyl substituted derivative with cyclopentadiene 8b are reported.

Regioselective syntheses of optically active (R)-5-methyl- and (R)-7-methyl-5,6,7,8-tetrahydroquinolines

Five synthetic routes have been evaluated for the regioselective preparation of (R)-5-methyl- and (R)-7-methyl-5,6,7,8-tetrahydroquinolines from (+)-(R)-3-methylcyclohexanone

4H-dinaphtho[2,1-f:1′,2′-h][1,5]dithionin-S,S′-tetroxide: Preparation, structure elucidation and facile intramolecular [2+2]-photocyclization

Abstract The preparation of compound 1, a conformational study in solution and the unexpectedly facile rearrangement into 2 via photochemical intramolecular [2+2]-cycloaddition is described: the structure of these compounds have been investigated by NMR and X-ray diffraction.

Regioselective Reductive Alkylation of 1,2,3-Trimethoxybenzene

Abstract The 2-methoxyl group of 1,2,3-trimethoxybenzene and its 5-methyl-substituted homologue is removed under reductive electron transfer conditions and replaced with an alkyl group in a one-pot procedure.