276:
136:
160:
261:
189:
is one of the most common procedures to produce formazans. Hydrazones, which are electron-rich compounds, react with diazonium salts either at a nitrogen or a carbon atom to produce formazans. Diazonium salts couple to the amine nitrogen in the hydrazone with displacement of a hydrogen to give the
155:
of such compounds results in their conversion into colorless tetrazolium salts. Among the various oxidants used are mercuric oxide, nitric acid, isoamyl nitrite, N-bromo succinimide, potassium permanganate, lead tetra-acetate and t-butyl hypochlorite. Depending on the conditions, tetrazolium salts
96:
flexibility. Due to the two alternating double bonds in the backbone, formazans can exist in four possible isomeric forms: syn, s-cis (closed form); syn, s-trans (open form); anti, s-cis; and anti, s-trans (linear form).
943:
Stockert, Juan C.; Blázquez-Castro, Alfonso; Cañete, Magdalena; Horobin, Richard W.; Villanueva, Ángeles (2012). "MTT assay for cell viability: Intracellular localization of the formazan product is in lipid droplets".
197:
compounds with diazonium salts. Diazonium salts add to active methylene compounds to form an intermediate azo compound, followed by the addition of a second diazonium salt (under more alkaline conditions), yielding
779:
Science of
Synthesis: Houben-Weyl Methods of Molecular Transformations Vol. 22: Three Carbon-Heteroatom Bonds: Thio-, Seleno-, and Tellurocarboxylic Acids and Derivatives; Imidic Acids and Derivatives; Ortho Acid
370:. In: Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). Online version (2019-) created by S. J. Chalk.
340:, the classical tetrazolium salt, MTT, turns blue to purple and may form an insoluble precipitate. These formazan dyes are commonly used in cell proliferation and toxicity
408:(Conference Issue (The 8th International Conference of The Textile Research Division (ICTRD 2017), National Research Centre, Cairo 12622, Egypt.)): 33–40.
1005:
Marshall NJ, Goodwin CJ, Holt SJ (June 1995). "A critical assessment of the use of microculture tetrazolium assays to measure cell growth and function".
57:. They have a variety of colors from dark blue to deep red to orange, depending on the original tetrazolium salt used as the substrate for the reaction.
233:
reacts at the methylene position to yield 3-methyl-1,5-diphenylformazan, which can also be obtained from the reaction of phenylazoethane with
1034:"Evaluation of a soluble tetrazolium/formazan assay for cell growth and drug sensitivity in culture using human and other tumor cell lines"
272:. These procedures are based on the reduction of tetrazolium by mitochondrial dehydrogenase enzymes, which is carried inside living cells:
398:"Synthesis and spectral properties of symmetrical and asymmetrical 3-cyano-1, 5-diarylformazan dyestuffs for dyeing polyester fabrics"
308:
or 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, which is water-soluble and used in the
889:"Tetrazolium salts and formazan products in Cell Biology: Viability assessment, fluorescence imaging, and labeling perspectives"
427:
787:
457:
919:
363:
595:
1053:
761:
728:
375:
324:
used in a diagnostic test, particularly for chronic granulomatous disease and other diseases of phagocyte function.
268:
Tetrazolium salts and their formazan products are widely used in histochemical methods, especially in colorimetric
719:
Karabach, Y.Y.; Kopylovich, Maximilian (2014). "Synthesis, applications and coordination chemistry of formazans".
65:
Formazans are intensely colorful compounds characterized by the following structure: , and are closely related to
321:
1033:
295:
or 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide, which is water-insoluble and used in the
560:"Formazanate Ligands as Structurally Versatile, Redox-Active Analogues of β-Diketiminates in Zinc Chemistry"
209:
of the corresponding hydrazidines, usually prepared via reaction of hydrazonyl halides with the appropriate
17:
302:
XTT or 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide, which is water-soluble.
616:
Katritzky, Alan R.; Belyakov, Sergei A.; Durst, H. Dupont; Xu, Ruixin; Dalal, Naresh S. (1994-08-01).
985:
93:
558:
Chang, Mu-Chieh; Roewen, Peter; Travieso-Puente, Raquel; Lutz, Martin; Otten, Edwin (2014-12-10).
289:
or 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride, which is water-insoluble.
105:
344:
such as the EpiDerm and EpiSkin tests since they only stain living, metabolically active cells.
241:
887:
Stockert, Juan C.; Horobin, Richard W.; Colombo, Lucas L.; Blázquez-Castro, Alfonso (2018).
142:
Due to their ability to react with both strong acids and bases, formazans can be considered
662:"Functionalized formazans: A review on recent progress in their pharmacological activities"
315:
100:
1,5-disubstituted formazans can exist as two tautomers (1 and 2 in the image below). Upon
8:
834:
696:
661:
179:
172:
865:
1045:
1014:
961:
911:
869:
838:
826:
783:
757:
724:
701:
683:
639:
587:
579:
540:
496:
453:
419:
371:
70:
953:
903:
861:
816:
749:
691:
673:
629:
571:
530:
486:
414:
409:
397:
379:
109:
244:
of substituted tetrazolium salts either photochemically or under the influence of
957:
907:
367:
269:
222:
194:
74:
888:
678:
360:
286:
777:
Charette, A.B.; Aggarwal, V.K.; Aitken, R.A.; Cicchi, S.; Cordero, F. (2014).
1081:
1075:
687:
643:
583:
519:"Formazanate coordination compounds: synthesis, reactivity, and applications"
500:
423:
230:
214:
101:
50:
753:
965:
915:
830:
821:
804:
705:
591:
544:
264:
MTT test: Formation of formazan crystals from MTT in mesenchymal stem cells
234:
218:
1049:
1018:
873:
491:
474:
275:
805:"Cytotoxic Activity of Herbal Medicines as Assessed in Vitro: A Review"
559:
535:
518:
159:
143:
135:
575:
1032:
Scudiero DA, Shoemaker RH, Paull KD, et al. (1 September 1988).
886:
383:
309:
305:
296:
292:
245:
210:
199:
186:
129:
66:
54:
42:
942:
634:
617:
260:
318:
or 2,3,5-triphenyl-2H-tetrazolium chloride, which is water-soluble.
183:
89:
82:
193:
Another form to synthesize formazans is by the reaction of active
329:
249:
121:
117:
113:
34:
are compounds of the general formula , formally derivatives of
803:
Gavanji S, Bakhtari A, Famurewa AC, Othman EM (January 2023).
721:
557:
802:
341:
337:
282:
Leading examples of the most used tetrazolium salts include:
206:
152:
78:
776:
69:(−N=N−) dyes. Their structure was first defined in 1892, by
333:
226:
125:
979:
744:
Daniel, DS (2002). "The
Chemistry of Tetrazolium Salts".
615:
156:
can be reduced to form tetrazolyl radicals or formazan:
618:"Syntheses of 3-(substituted)-2,4,6-triphenylverdazyls"
1031:
852:
Altman FP (1976). "Tetrazolium salts and formazans".
190:
intermediate, which then rearranges to the formazan.
77:
27:
Class of chemical compounds; intensely colorful dyes
1004:
718:
475:"The Chemistry of Formazans and Tetrazolium Salts"
128:, etc), formazans form highly coloured complexes (
1073:
936:
880:
240:Additionally, formazans can be obtained by the
723:. Nova Science Publishers. pp. 249–274.
447:
395:
202:, which then forms a 3-substituted formazan.
660:Shawali, Ahmad S.; Samy, Nevien A. (2015).
659:
516:
60:
396:Khattab, Tawfik; Haggag, Karima M (2017).
851:
820:
695:
677:
655:
653:
633:
534:
490:
413:
512:
510:
259:
171:There various synthetic methods for the
104:, the formed anion (3) is stabilized by
472:
14:
1074:
743:
650:
205:Formazans can also be produced by the
1056:from the original on 24 February 2022
517:Gilroy, Joe B.; Otten, Edwin (2020).
507:
225:to yield 1,5-diphenylformazan, under
737:
448:Wolfrom, M.L.; Tipson, R.S. (1958).
24:
450:Advances in Carbohydrate Chemistry
274:
158:
134:
45:products obtained by reduction of
25:
1093:
332:or through direct reaction with
1025:
998:
988:from the original on 2022-02-08
972:
925:from the original on 2022-01-20
845:
796:
770:
598:from the original on 2022-02-24
430:from the original on 2020-10-18
328:When reduced in a cell, either
221:reacts with two equivalents of
712:
609:
551:
466:
441:
415:10.21608/ejchem.2017.1479.1103
389:
354:
255:
13:
1:
866:10.1016/S0079-6336(76)80015-0
622:Canadian Journal of Chemistry
473:Nineham, A. W. (1955-04-01).
402:Egyptian Journal of Chemistry
347:
41:Formazan dyes are artificial
958:10.1016/j.acthis.2012.01.006
908:10.1016/j.acthis.2018.02.005
809:Chemistry & Biodiversity
666:Journal of Advanced Research
166:
81:chemistry derive from their
7:
746:Topics in Applied Chemistry
316:TTC or tetrazolium chloride
10:
1098:
679:10.1016/j.jare.2014.07.001
452:. ISSN. Elsevier Science.
229:. Under basic conditions,
213:derivatives. For example,
854:Prog. Histochem. Cytochem
61:Structure and reactivity
38:, unknown in free form.
754:10.1007/0-306-46906-5_7
822:10.1002/cbdv.202201098
279:
265:
163:
139:
88:Formazans have a high
278:
263:
162:
138:
564:Inorganic Chemistry
492:10.1021/cr50002a004
180:diazonium compounds
536:10.1039/C9CS00676A
366:2022-01-20 at the
280:
266:
164:
140:
946:Acta Histochemica
896:Acta Histochemica
789:978-3-13-178151-2
576:10.1021/ic5025873
459:978-0-08-056272-8
227:acidic conditions
47:tetrazolium salts
16:(Redirected from
1089:
1066:
1065:
1063:
1061:
1029:
1023:
1022:
1002:
996:
995:
994:
993:
976:
970:
969:
940:
934:
933:
931:
930:
924:
893:
884:
878:
877:
849:
843:
842:
824:
800:
794:
793:
774:
768:
767:
741:
735:
734:
716:
710:
709:
699:
681:
657:
648:
647:
637:
628:(8): 1849–1856.
613:
607:
606:
604:
603:
555:
549:
548:
538:
514:
505:
504:
494:
479:Chemical Reviews
470:
464:
463:
445:
439:
438:
436:
435:
417:
393:
387:
384:10.1351/goldbook
358:
270:viability assays
178:The reaction of
110:transition metal
85:-rich backbone.
21:
1097:
1096:
1092:
1091:
1090:
1088:
1087:
1086:
1072:
1071:
1070:
1069:
1059:
1057:
1044:(17): 4827–33.
1030:
1026:
1003:
999:
991:
989:
978:
977:
973:
941:
937:
928:
926:
922:
891:
885:
881:
850:
846:
801:
797:
790:
775:
771:
764:
742:
738:
731:
717:
713:
658:
651:
635:10.1139/v94-235
614:
610:
601:
599:
556:
552:
515:
508:
471:
467:
460:
446:
442:
433:
431:
394:
390:
368:Wayback Machine
359:
355:
350:
258:
235:isoamyl nitrite
223:phenylhydrazine
169:
149:
63:
28:
23:
22:
15:
12:
11:
5:
1095:
1085:
1084:
1068:
1067:
1024:
997:
971:
952:(8): 785–796.
935:
902:(3): 159–167.
879:
844:
795:
788:
769:
762:
736:
729:
711:
672:(3): 241–254.
649:
608:
570:(1): 379–388.
550:
523:Chem. Soc. Rev
506:
485:(2): 355–483.
465:
458:
440:
388:
352:
351:
349:
346:
326:
325:
319:
313:
303:
300:
290:
257:
254:
175:of formazans.
168:
165:
94:conformational
62:
59:
51:dehydrogenases
26:
9:
6:
4:
3:
2:
1094:
1083:
1080:
1079:
1077:
1055:
1051:
1047:
1043:
1039:
1035:
1028:
1020:
1016:
1012:
1008:
1001:
987:
983:
982:
975:
967:
963:
959:
955:
951:
947:
939:
921:
917:
913:
909:
905:
901:
897:
890:
883:
875:
871:
867:
863:
859:
855:
848:
840:
836:
832:
828:
823:
818:
814:
810:
806:
799:
791:
785:
781:
773:
765:
763:0-306-45459-9
759:
755:
751:
747:
740:
732:
730:9781631171437
726:
722:
715:
707:
703:
698:
693:
689:
685:
680:
675:
671:
667:
663:
656:
654:
645:
641:
636:
631:
627:
623:
619:
612:
597:
593:
589:
585:
581:
577:
573:
569:
565:
561:
554:
546:
542:
537:
532:
529:(1): 85–113.
528:
524:
520:
513:
511:
502:
498:
493:
488:
484:
480:
476:
469:
461:
455:
451:
444:
429:
425:
421:
416:
411:
407:
403:
399:
392:
385:
381:
377:
376:0-9678550-9-8
373:
369:
365:
362:
357:
353:
345:
343:
339:
335:
331:
330:enzymatically
323:
320:
317:
314:
311:
307:
304:
301:
298:
294:
291:
288:
285:
284:
283:
277:
273:
271:
262:
253:
251:
247:
246:ascorbic acid
243:
242:decomposition
238:
236:
232:
231:ethyl nitrate
228:
224:
220:
216:
215:ethyl formate
212:
208:
203:
201:
196:
191:
188:
185:
181:
176:
174:
161:
157:
154:
150:
147:
145:
137:
133:
131:
127:
123:
119:
115:
111:
107:
103:
102:deprotonation
98:
95:
91:
86:
84:
80:
76:
72:
68:
58:
56:
52:
48:
44:
39:
37:
33:
19:
1058:. Retrieved
1041:
1037:
1027:
1013:(2): 69–84.
1010:
1007:Growth Regul
1006:
1000:
990:, retrieved
980:
974:
949:
945:
938:
927:. Retrieved
899:
895:
882:
857:
853:
847:
812:
808:
798:
778:
772:
745:
739:
720:
714:
669:
665:
625:
621:
611:
600:. Retrieved
567:
563:
553:
526:
522:
482:
478:
468:
449:
443:
432:. Retrieved
405:
401:
391:
356:
327:
281:
267:
239:
219:orthoformate
204:
192:
177:
170:
151:
148:
141:
99:
87:
71:von Pechmann
64:
46:
40:
35:
31:
29:
1060:24 February
860:(3): 1–56.
815:(2): 3–27.
780:Derivatives
748:: 207–296.
256:Application
43:chromogenic
18:Tetrazolium
1038:Cancer Res
992:2022-02-24
929:2022-02-24
782:. Thieme.
602:2022-02-24
434:2022-02-24
348:References
187:hydrazones
144:amphoteric
90:tautomeric
55:reductases
839:255473013
688:2090-1232
644:0008-4042
584:0020-1669
501:0009-2665
424:0449-2285
361:formazans
310:MTS assay
297:MTT assay
211:hydrazine
207:oxidation
200:tetrazene
195:methylene
173:synthesis
167:Synthesis
153:Oxidation
106:resonance
75:Bamberger
32:formazans
1076:Category
1054:Archived
986:archived
966:22341561
920:Archived
916:29496266
831:36595710
706:26257923
596:Archived
592:25493709
545:31802081
428:Archived
364:Archived
252:medium.
250:alkaline
184:aldehyde
130:chelates
83:nitrogen
36:formazan
1050:3409223
1019:7627094
697:4522548
108:. With
73:and by
1048:
1017:
981:Mattek
964:
914:
874:792958
872:
837:
829:
786:
760:
727:
704:
694:
686:
642:
590:
582:
543:
499:
456:
422:
374:
342:assays
248:in an
112:ions (
923:(PDF)
892:(PDF)
835:S2CID
338:NADPH
182:with
79:redox
1082:Dyes
1062:2022
1046:PMID
1015:PMID
962:PMID
912:PMID
870:PMID
827:PMID
784:ISBN
758:ISBN
725:ISBN
702:PMID
684:ISSN
640:ISSN
588:PMID
580:ISSN
541:PMID
497:ISSN
454:ISBN
420:ISSN
372:ISBN
334:NADH
92:and
53:and
30:The
954:doi
950:114
904:doi
900:120
862:doi
817:doi
750:doi
692:PMC
674:doi
630:doi
572:doi
531:doi
487:doi
410:doi
380:doi
336:or
322:NBT
306:MTS
293:MTT
287:INT
217:or
132:).
67:azo
49:by
1078::
1052:.
1042:48
1040:.
1036:.
1009:.
984:,
960:.
948:.
918:.
910:.
898:.
894:.
868:.
856:.
833:.
825:.
813:20
811:.
807:.
756:.
700:.
690:.
682:.
668:.
664:.
652:^
638:.
626:72
624:.
620:.
594:.
586:.
578:.
568:54
566:.
562:.
539:.
527:49
525:.
521:.
509:^
495:.
483:55
481:.
477:.
426:.
418:.
406:60
404:.
400:.
378:.
237:.
146:.
126:Zn
124:,
122:Ni
120:,
118:Co
116:,
114:Cu
1064:.
1021:.
1011:5
968:.
956::
932:.
906::
876:.
864::
858:9
841:.
819::
792:.
766:.
752::
733:.
708:.
676::
670:6
646:.
632::
605:.
574::
547:.
533::
503:.
489::
462:.
437:.
412::
386:.
382::
312:.
299:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
