4809. Hydroxocobalamin

Nomenclature

CAS number: 13422-51-0
Co-Hydroxycobinamide f-(dihydrogen phosphate) inner salt 3′-ester with (5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole-κN3); cobinamide hydroxide dihydrogen phosphate (ester) inner salt 3′-ester with 5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole; α-(5,6-dimethylbenzimidazolyl)hydroxocobamide; vitamin B12a; hydroxocobemine; OHB12; Cobalin-H (Link); Dodécavit (Serb); Duradoce (Atlantis); Neo-Cytamen (Medeva); Redisol H (Merck & Co.).
C62H89CoN13O15P; mol wt 1346.36.
C 55.31%, H 6.66%, Co 4.38%, N 13.52%, O 17.83%, P 2.30%.

Description and references

Physiological analog of vitamin B12 where the CN group is replaced with OH. Exists in aq soln as an equilibrium mixture of the hydroxy isomer and the ionic aqua isomer (aquacobalamin). Precursor of the coenzymes methylcobalamin and cobamamide, q.q.v. Prepn: E. A. Kaczka et al., J. Am. Chem. Soc. 71, 1514 (1949) DOI PubMed; eidem, ibid. 73, 335 (1951) DOI; eidem, US 2738301 (1956 to Merck & Co.). Acids replace the hydroxo group with the anion of the acid: eidem, Science 112, 354 (1950). Prepn from cyanocobalamin: R. Bieganowski, G. Klar, Chem. Ztg. 106, 235 (1982). HPLC determn in plasma: A. Astier, F. J. Baud, J. Chromatogr. B 667, 129 (1995) DOI PubMed. Clinical evaluation as antidote to cyanide in smoke inhalation: S. W. Borron et al., Ann. Emerg. Med. 49, 794 (2007) DOI PubMed. Review: “Vitamin B12” in Vitamins, W. Friedrich, Ed. (de Gruyter, Berlin, 1988) pp 837-928. Review of clinical use for acute cyanide poisoning: G. Shepherd, L. I. Velez, Ann. Pharmacother. 42, 661-669 (2008) DOI PubMed.

Chemical structure

Properties

Dark red, orthorhombic needles or platelets from water + acetone. Darkens at 200°, but not melted at 300°. Absorption max (H2O): 279, 325, 359, 516, 537 nm (ε 19000, 11400, 20600, 8900, 9500). Moderately sol in water and in the lower aliphatic alcohols. Practically insol in acetone, ether, petr ether, halogenated hydrocarbons, benzene.

Derivative

Aquacobalamin.

Nomenclature

CAS number: 13422-52-1
Co-Aquacobinamide dihydrogen phosphate (ester) inner salt 3′-ester with (5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole-κN3) ion(1+) hydroxide (1:1); aquocobalamin; vitamin B12b; vitamin B12d.
C62H90CoN13O15P.OH; mol wt 1364.37.
C 54.58%, H 6.72%, Co 4.32%, N 13.35%, O 18.76%, P 2.27%.

Properties

Absorption max (H2O): 274, 317, 351, 499, 527 nm (ε 20600, 6100, 26500, 8100, 8500).

Derivative

Acetatocobalamin.

Nomenclature

CAS number: 22465-48-1
Co-(Acetato-κO)-cobinamide dihydrogen phosphate (ester) inner salt 3′-ester with (5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole-κN3); Depogamma (Woerwag); Docelan (Aventis); Novidroxin (Fatol).
C64H91CoN13O16P; mol wt 1388.39.
C 55.37%, H 6.61%, Co 4.24%, N 13.11%, O 18.44%, P 2.23%.

Description and references

Prepn of stable solns: Marcus et al., FR 1336671 (1963 to Merck & Co.), C.A. 60, 380a (1964).

Derivative

Nitrocobalamin.

Nomenclature

CAS number: 20623-13-6
Co-(Nitrito-κO)-cobinamide dihydrogen phosphate (ester) inner salt 3′-ester with (5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole-κN3); nitritocobalamin; vitamin B12c.
C62H88CoN14O16P; mol wt 1375.35.
C 54.14%, H 6.45%, Co 4.28%, N 14.26%, O 18.61%, P 2.25%.

Description and references

Prepn: E. A. Kaczka et al., J. Am. Chem. Soc. 73, 3569 (1951) DOI.

Properties

Red crystalline solid. Absorption max in water: 352, 527.5 nm (E1%1cm 153.2, 59.5); in 0.01N NaOH: 357, 535 nm (E1%1cm 139, 62.5).

Derivative

Sulfitocobalamin.

Nomenclature

CAS number: 15671-27-9
Co-(Sulfito-κO)-cobinamide dihydrogen phosphate (ester) inner salt 3′-ester with (5,6-dimethyl-1-α-d-ribofuranosyl-1H-benzimidazole-κN3); cobalaminsulfonic acid.
C62H89CoN13O17PS; mol wt 1410.42.
C 52.80%, H 6.36%, Co 4.18%, N 12.91%, O 19.28%, P 2.20%, S 2.27%.

Description and references

Prepn: Fricke, US 2721162 (1955 to Abbott).

Properties

Absorption max: 275, 365, 418, 516 nm (E1%1cm 328, 130, 49, 61).

Therapeutic Category

Vitamin (hematopoietic). Hydroxocobalamin as antidote to cyanide poisoning.

Therapeutic Category (Veterinary)

Vitamin (hematopoietic).

Keywords

Vitamin/Vitamin Source; Vitamin B12; Antidote (Cyanide)