Nitrosyl synthesis

Alkyl nitrites have also been used in nitrosyl synthesis and their mode of action may be explained by analogy with the above. One can consider that initial coordination of RONO is quickly followed by H+ attack giving a free alcohol and the nitrosyl complex (equation 12). 

It is possible that in the use of alkali metal nitrites for nitrosyl synthesis, the first formed nitrito complex undergoes rapid ligand reduction similar to that above, as in equations (15) and (16). 

A photochemical partial synthesis of aldosterone (19) made the hormone available on an industrial scale for the first time (114). Corticosterone acetate (51 acetate) is treated with nitrosyl chloride in pyridine at 20°C to yield the 11-nitrite (115). Irradiation of (115) leads to rearrangement with formation of the C g-oxime (116). Removal of the oxime residue with nitrous acid furnishes aldosterone (19) in excellent yield. 

Equations 4-8 illustrate some mild methods that can be used to cleave amides. Equations 4 and 5 indicate the conditions that were used by Woodward and Eschenmoser, respectively, in their synthesis of vitamin B,2- Butyl nitrite," nitrosyl chloride, and nitrosoniurn tetrafluoroborate... 

Whereas sulfonyl halides have been known for a long time and, especially the chlorides, have become of great synthetic value, sulfonyl cyanides were unknown until 1968. They were first prepared by van Leusen and co-workers from the reaction of sulfonylmethylenephos-phoranes with nitrosyl chloride. The same group also investigated part of their chemistry. Since then, two more, completely different, methods of synthesis were published from sulfinates with cyanogen chloride,and by the oxidation of thiocyanates. ... 

Equations 1-10 illustrate some mild methods that can be used to cleave amides. Equations 1 and 2 indicate the conditions that were used by Woodward and Eschenmoser, respectively, in their synthesis of vitamin B12. Butyl nitrite, nitrosyl chloride, and nitrosonium tetrafluoroborate (NO BF4 ) have also been used to cleave amides. Since only tertiary amides are cleaved by potassium -butoxide (eq. 3), this method can be used to effect selective cleavage of tertiary amides in the presence of primary or secondary amides.(Esters, however, are cleaved by similar conditions.) Photolytic cleavage of nitro amides (eq. 4) is discussed in a review. 

Sulfonic acids containing nitrogen have long been implicated as essential intermediates in the synthesis of H2SO4 by the lead-chamber process (p. 708) and, as shown by F. Seel and his group, the crucial stage is the oxidation of sulfite ions by the nitrosyl ion NO+ ... 

The required nitrite esters 1 can easily be obtained by reaction of an appropriate alcohol with nitrosyl chloride (NOCl). The 3-nitroso alcohols 2 formed by the Barton reaction are useful intermediates for further synthetic transformations, and might for example be converted into carbonyl compounds or amines. The most important application for the Barton reaction is its use for the transformation of a non-activated C-H group into a functional group. This has for example been applied for the functionalisation of the non-activated methyl groups C-18 and C-19 in the synthesis of certain steroids. ... 

Synthesis of this compound from a 15N labelled source revealed that the i4N and 15N were equally distributed between the apical bent nitrosyl (NO-) and equatorial linear nitrosyl (NO+) ... 

Figure 2.100 Synthesis of some iridium nitrosyl complexes.

Figure 2.101 Synthesis of some rhodium nitrosyl complexes.

Transition metal nitrosyls in organic synthesis and in pollution control. K. K. Pondey, Coord. Chem. Rev., 1983, 51, 69-98 (143). 

The synthetic utility of the mercuration reaction derives from subsequent transformations of the arylmercury compounds. As indicated in Section 7.3.3, these compounds are only weakly nucleophilic, but the carbon-mercury bond is reactive to various electrophiles. They are particularly useful for synthesis of nitroso compounds. The nitroso group can be introduced by reaction with nitrosyl chloride73 or nitrosonium tetrafluoroborate74 as the electrophile. Arylmercury compounds are also useful in certain palladium-catalyzed reactions, as discussed in Section 8.2. 

Table 9.42 Synthesis ofisoxazoles from nitrosyl fluoroborate and allenylsilanes.

J Honzl, J Rudinger. Amino acids and peptides. XXXIII. Nitrosyl chloride and butyl nitrite as reagents in peptide synthesis by the azide method suppression of amide formation. Coll Czech Chem Commun 26, 2333, 1961. 

Osterloh, F., Saak, W, Haase, D. and Pohl, S. (1997) Synthesis, X-ray structure and electrochemical characterization of a binuclear thiolate bridged Ni-Fe-nitrosyl complex, related to the active site of NiFe hydrogenase. Chem. Commun. (Cambridge), 1997, 979-80. 

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