吉田 和弘

Cyclam is a well‐known example of a polyaza macrocycle. However, there are few reports of its optically active versions. In this study, we synthesized highly symmetric optically active cyclam (S,S,S,S)‐5,7,12,14‐tetraphenyl‐1,4,8,11‐tetraazacyclotetradecane, which has four phenyl groups on the cyclam skeleton, and derivatized it in various ways. We were able to synthesize a chiral Cu complex, an N‐ethyl derivative, and a dithiourea from this optically active cyclam. The structures of the chiral Cu complex and dithiourea were verified by single‐crystal X‐ray diffraction analysis.

Abstract [1]Benzothieno[3,2‐b][1]benzothiophenes (BTBTs) are important molecules that have been extensively studied as high‐performance organic field‐effect transistors (OFETs). Therefore, it is important to develop a simple synthetic method for these molecules. In this paper, a synthetic method to obtain the BTBTs from 2‐arylbenzo[b]thiophenes and elemental sulfur, in which two C−S bonds are formed at once, is described. In this method, molecular iodine plays a very important role as an additive. The role of iodine is discussed in the presumed reaction pathways.

Abstract Treatment of N-propargyl-N′-tosylhydrazines with molecular iodine (I2) in the presence of NaHCO3 under warming conditions gave efficiently the corresponding 5-substituted 4-iodo-1-tosylpyrazoles in good to moderate yields. In addition, the same reaction in the presence of acetic acid generated the corresponding 5-aryl-4-iodopyrazoles in moderate yields. The reactions are simple and efficient transition-metal-free methods for the preparation of 5-substituted 4-iodo­pyrazole unit.

The treatment of easily accessible o-(1-hydroxy-2-alkynyl)-N-tosylanilides 1 with excess manganese(IV) oxide in the presence of substoichiometric tetrabutylammonium iodide (TBAI) in chloroform (or in the absence of TBAI in dimethylformamide, DMF) promoted a sequential oxidation/intramolecular hydroamination to give 4-quinolones 3 and/or (Z)-2-alkylidene-3-oxindoles (Z)-4 in good yields. Possibly, MnO2 played dual roles as an oxidant and as a Lewis acidic activator of intermediary ynones 2. The product distributions between 3 and (Z)-4 could be controlled by the choice of solvents.