Reaktionsgleichung
[NH2:1][C:2]1[CH:12]=[CH:11][C:5]2[N:6]=[C:7]([C:9]#[N:10])[S:8][C:4]=2[C:3]=1[C:13]#[N:14].CO[CH:17](OC)[N:18]([CH3:20])[CH3:19]>>[C:9]([C:7]1[S:8][C:4]2[C:3]([C:13]#[N:14])=[C:2](/[N:1]=[CH:17]/[N:18]([CH3:20])[CH3:19])[CH:12]=[CH:11][C:5]=2[N:6]=1)#[N:10]Komponenten
Versuchsvorschrift
The thiazolo[5,4-f]quinazoline-2-carbonitriles VIIIaa-ib were prepared following scheme 1: N-Boc Protection of 2-amino-5-nitrobenzonitrile using di-tert-butyl dicarbonate in a suitable solvent, such as dichloromethane, in presence of suitable bases such as triethylamine and 4-(dimethylamino)pyridine and preferably at room temperature, provides tert-butyl (2-cyano-4-nitrophenyl)carbamate I in high yield. Reduction of the nitro intermediate I, for example by treatment with ammonium formate and a catalytic amount of 10% palladium charcoal preferably in ethanol under microwave irradiation for preferably 30 min at 600 W, provides tert-butyl 4-amino-2-cyanophenylcarbamate II in high yield. Treatment of intermediate II by a solution of bromine in dichloromethane in a suitable solvent, such as acetic acid, preferably at room temperature provides tert-butyl 4-amino-3-bromo-2-cyanophenylcarbamate III in a quantitative yield. Intermediate III is reacted with Appel's salt (4,5-dichloro-1,2,3-dithiazolium chloride) (Appel, R. et al., Chem. Ber., 1985, 118, 1632) preferably in dichloromethane at room temperature to afford (Z)-tert-butyl-3-bromo-4-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)-2-cyanophenylcarbamate IV. N-Boc deprotection of intermediate IV using di-tert-butyl dicarbonate in a suitable solvent, such acetic acid, preferably under microwave irradiation at 118° C. provides (Z)-6-amino-2-bromo-3-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)benzonitrile V in a quantitative yield. Cyclization of intermediate V may be accomplished by treatment with copper iodide in a suitable solvent, such as pyridine, preferably under microwave irradiation at 400 W at 130° C. for 20 min to obtain 6-aminobenzo[d]thiazole-2,7-dicarbonitrile VI in good yield (Besson, T. et al., J. Chem. Soc., Perkin Trans. 1, 1998, 3925). Treatment of intermediate VI in a suitable solvent, such as dimethylformamide dimethylacetal, preferably under microwave irradiation at 70° C. (600 W) gives (E)-N′-(2,7-dicyanobenzo[d]thiazol-6-yl)-N,N-dimethylformimidamide VII in good yield. Cyclization of intermediate VII in thiazolo[5,4-f]quinazoline-2-carbonitriles VIIIaa-ib may be accomplished by a Dimroth rearrangement using the appropriate aniline or primary amine R3NH2 (preferably 1.5 equivalent) in a suitable solvent, such acetic acid and preferably under microwave irradiation at 118° C. (600 W) (Foucourt, A. et al., Tetrahedron, 2010, 66, 4495).
Aufarbeitung
- customin good yield (Besson, T. et al., J. Chem. Soc., Perkin Trans. 1, 1998, 3925)
Quellen und Nachweise
- ORD-Eintrag
- ord-4b2a5b8242804af98ffb34900c9b25e0
- Quelldatensatz
- uspto-grants-2016_09
- Patentnummer
- US09446044B2
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