5,6-Dihydro-3-(5-nitro-2-furyl)imidazo[2,1-b]thiazoles and Acid Addition Salts¹

Abstract

Yol. 9 B. Irreversibility of the Disproportionation.-Cystamine dihydrochloride (0.5 mmole) was heated with 0.5 mmole of phenyl disulfide, o-chlorophenyl disulfide, or o-hvdroxymethylphenyl disulfide, as usual for disproportionation experiments, in 10 ml of water at 100°for 72 hr. The three aryl disulfides were recovered unchanged (mixture melting point and infrared spectrum) in yields of 99, 104, and l()Lr0 respectively.C. Material Balance in the Disproportionation of 2-Aminoethyldithiobenzene Hydrochloride (10).-An aqueous solution of 10 (0.2338 g, 1.054 mmoles) in water (10 ml) was heated at 08°e xactly as in the disproportionation of 2 -7, except that a 10-day period was used to assure nearly complete reaction. Phenyl disulfide was extracted with CHCh; yield, 105.8 mg (92R ): mj) and inntp 58-59°( infrared spectrum identical with that of phenyl disulfide). Thin layer chromatography was performed on this solid, along with the aqueous phase and appropriate authentic samples, on Eastman Chromagram sheet (Type K 301K: previously activated at 110°for 0.5 hr). Development with 957) acetic acid for 2 hr and exposure to iodine vapor showed one spot, with li; 0.81 (identical witli authentic phenyl disulfide) and only two other spots, with li¡ values of 0.40 and 0.06 corresponding to the authentic samples of cystamine dihydrochloride and 10, respectively.The aqueous phase was evaporated under reduced pressure to a white residue. The residue was rubbed with cold absolute ethanol, which removed 10 but left most of the cystamine salt. Evaporation of the ethanol left crude 10. Several applications of this procedure finally separated 29.6 mg (13$c•) of 10, mp and mmp 127-131°, and 102.6 mg (S6C)) of cystamine dihvdro-chloride, mp and mmp 218-220°dec. Infrared spectra for 10 and the cystamine salt were identical with those of authentic material. Since thin layer chromatography showed that, only three materials were present and since separation showed these materials to be the two symmetrical disulfides (86-92'))) and unchanged 10 (13')), evidently still containing a little cystamine salt), the disproportionation must proceed rather cleanly with rattier slight formation of by-products.Photochemical Disproportionation of Disulfides 2-7 and 9. Aqueous solutions of 1 mmole of unsymmetrical disulfide in 20 ml of water (0.05 .1/) in 50-ml Pyrex flasks23 were irradiated at a distance of 12.5 cm with an ultraviolet source (l()()-w Hanovia ultraviolet lain]), Engelhard Industries Inc.. Newark, N. J.) for 25 min at room temperature. Isolations and calculations were done in the same maimer described for thermal disproportionation.Acknowledgment.-We arc indebted to I)rs. T. It. Sweeney, D. P. Jacobus, and P. Goad for helpful suggestions, as well as for testing and for certain materials mentioned above. The research was supported by the V. S. Army Medical Research and Development Command, Department of the Army, under Research Contract• No. DA-49-193-MD-2030. (24,i liumoyentOUS solution of sparingly .soluble 9 was prepared by dissolvi...

A Multistep Preparation of 3-Aryl-8-methoxythiazolo [3’, 2’ : 2, 3] [1, 2, 4] triazino [5, 6-b] indoles Under Microwave IR-radiations

“…containing thiazole and related heterocycles (thiadiazole and thiadiazine) exhibit antihistaminic, antithyroid, antitubercular, antifungal & antibacterial activities [1][2][3] and their synthetic importance has been greatly enhanced by the recent uses of their condensed bridgehead nitrogen heterocycles as anthelminitics, antidepressants, platelet aggregation inhibitors, antineoplastic, vulcanization accelerators and photographic sensitizers [4][5][6][7][8][9][10][11] . The indoles are already been synthesized by different method But they requires longer reaction time and tedious workup [12][13][14][15][16][17][18][19][20][21] .…”

“…ethanol under microwave irradiation at 560W for 5-minutes to give 6-Methoxyisatin-3-thiosemicarbanzone (I). After separation, the 6-Methoxyisatin-3-thiosemicarbanzone(I) reacts with 5% KOH under microwave irradiation at 560W for 5-minutes to give 7-Methoxy-5H-2,3-dihydro [1,2,4] triazino [5, 6-b] indole-3-thione (II).…”

“…The compound 7-Methoxy-5H-2,3-dihydro [1,2,4] triazino [5, 6-b] indole-3-thione (II) further reacts with p-chlorophenacyl bromide under microwave irradiation at 560W for 5-minutes to give 5H-3-(p-chlorophenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] indole hydrobromide (IIIa; Ar = p-C1C 6 H 4 ). Similarly, 7-Methoxy-5H-2,3-dihydro [1,2,4] triazino [5, 6-b] indole-3-thione(II) was also irradiated with p-cholorophenacyl bromide, phenacyl bromide, under microwave irradiation at 560W for 5-minutes to give 5H-3-(p-bromophenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] indole hydrobromide(IIIb, Ar = p-Br C 6 H 4 ) and 5H-3-(phenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] indole hydrobromide (IIIa; Ar = C 6 H 5 ) respectively.…”

“…Similarly, 7-Methoxy-5H-2,3-dihydro [1,2,4] triazino [5, 6-b] indole-3-thione(II) was also irradiated with p-cholorophenacyl bromide, phenacyl bromide, under microwave irradiation at 560W for 5-minutes to give 5H-3-(p-bromophenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] indole hydrobromide(IIIb, Ar = p-Br C 6 H 4 ) and 5H-3-(phenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] indole hydrobromide (IIIa; Ar = C 6 H 5 ) respectively. The results are shown in Table-1. We further explore our work by irradiated 5H-3-(p-chlorophenacylthio-7-methoxy [1,2,4] triazino [5, 6-b] Table-2.…”

Eco-friendly synthesis of 1-Aryl-8-methoxythiazolo [2’, 3’ : 3, 4] [1, 2, 4] triazino [5, 6-b] indoles under microwave ir-radiations

“…The present work reports the synthesis of 1-Aryl-8-methoxythiazolo [2', 3' : 3, 4] [1,2,4] triazino [5, 6-b] indoles in a multi-step preparation in high yield in shorter reaction time(Scheme-I). Our work started by reacting 6-methoxyisatin with thiosemicarbazide in Anhyd.…”