H. Dehne

Infrared spectroscopic and thermal analytical investigations on the polymorphism of N-arylsulphonyl isothioureas

Abstract34 compounds containing the SO2-N-C-N-moiety are investigated by means of infrared spectroscopy and differential scanning calorimetry to study problems of polymorphic species. There are arguments for different crystalline solids of 16 sulphonyl derivatives. The phenomenon of polymorphism can be discussed both in terms of different hydrogen bonding and conformational effects. Although two tautomers are thinkable for the compounds being investigated the sulphonylimino structure is assumed to yield the most stable state.

DERIVATIVES OF TRANS 5-AROYL-3,4-DIARYLTHIAZOLIDINE-2-IMINES

Abstract The synthesis of trans 5-aroyl-3,4-diarylthiazolidine-2-iminium chlorides 2 or trans 2-aroyl-1-aryl-1,2-dihydro-thiazolo[3,2-a]quinazoline-5-ones 3 by treatment of threo 1,3-diary-3-arylamino-2-thiocyanatopropanones 1 with dry hydrogen chloride is described. The reaction of the salts 2 with several acid chlorides yields the corresponding 2-(aroylimino), 2-(arylsulfenylimino) and 2-(arylsulfonylimino) substituted thiazolidines 6, 7 and 8, respectively.

THIOOXALSAURE-2-AMID-1-HYDRAZID-2-HYDRAZON : EINE NEUE ZWITTERIONISCHE VERBINDUNG

Abstract The reaction of sodium cyanodithioformate (NaSC(S)CN · 3DMF) with hydrazine hydrate gives thiooxalic acid 2-amide-1-hydrazide-2-hydrazone in good yields. Spectroscopic data, X-ray analysis, and the chemical behaviour prove the zwitterionic structure of this compound.

UNGEWÖHNLICHE BILDUNG VON 3-AROYLIMINO-5-ARYLAMINO-3H-1, 2, 4-DITHIAZOLEN

Abstract The reaction of 1, 3-diaryl-3-arylamino-2-thiocyanato-propanones 9 and aroylisothiocyanates was studied. 3-Aroylimino-5-arylamino-3H-1, 2, 4-dithiazoles 11 were formed in this unusual pathway by several fragmentation and rearrangement steps. The structure of the prepared compounds was confirmed by X-ray analysis of 11b.

A correlative IR, MS, 1H, 13C and 15N NMR and theoretical study of 4-arylthiazol-2(3H)-ones

Sixteen 4-arylthiazol-2(3H)-ones (3) were synthesised by cyclisation of α-thiocyanatoacetophenones (1) in acid solution. They appear to prefer greatly the oxo tautomeric forms. In CCl4 solution an equilibrium between the free CO bond and a “dimeric” hydrogen-bonded form exists in which the latter predominates. Several IR and NMR (1H, 13C and 15N) spectral properties are shown to correlate with Hammett σ-values and/or atomic Mulliken charges and bond orders, the latter being estimated by PM3 or AM1 semiempirical methods. The electron-impact mass spectra were also recorded and the fragmentation mechanisms interpreted in terms of the energetics of the ionic species. In addition, the geometric and electronic properties of 4-phenylthiazol-2(3H)-one (3a) and the related benzothiazol-2(3H)-one (4) based on ab initio HF/6-31 G* calculations are compared with each other.

REACTIONS OF A ZWITTERIONIC BENZYLIDENE COMPOUND OF THIOOXALIC ACID HYDRAZIDE AMIDE HYDRAZONE WITH C1-BUILDING BLOCKS

Abstract The zwitterionic 4-methoxybenzylidene derivative of thiooxalic acid hydrazide amide hydrazone 1 reacts with orthocarboxylic esters to 2,5-disubstituted I,3,4-thiadiazoles 2 and with carbon disulfide or 1,1′-carbonyldiimidazole to the corresponding 2,3-dihydro-1,3,4-thiadiazoles 4 and 5. The acyclic zwitterionic products 3 were obtained from 1 with aromatic acyl chlorides. X-Ray structural data of 2a and 2b are given. All compounds are characterized by spectroscopic data (1H NMR, 13C NMR, IR).