Sulfonic hydrazides

Sulfonic acid hydrazides, RSO2NHNH2, are prepared by the reaction of hydraziae and sulfonyl haUdes, generally the chloride RSO2CI. Some of these have commercial appHcations as blowiag agents. As is typical of hydrazides generally, these compounds react with nitrous acid to form azides (26), which decompose thermally to the very reactive, electron-deficient nitrenes (27). The chemistry of sulfonic acid hydrazides and their azides has been reviewed (87). 

All the sulfonic acid hydrazides are made from hydrazine or semicarbazide and the appropriate sulfonyl chloride in the presence of an HCl acceptor such as ammonia. 

This reaction, parallel with 10-77, is the standard method for the preparation of sulfonyl halides. Also used are PCI3 and SOCI2, and sulfonic acid salts can also serve as substrates. Sulfonyl bromides and iodides have been prepared from sulfonyl hydrazides (ArS02NHNH2, themselves prepared by 10-126) by treatment with bromine or iodine.Sulfonyl fluorides are generally prepared from the chlorides, by halogen exchange. 

DNA and RNA may be modified with hydrazide-reactive probes by reacting their cytosine residues with bisulfite to form reactive sulfone intermediates. These derivatives undergo transamination to couple hydrazide- or amine-containing probes (Draper and Gold, 1980) (Chapter 27, Section 2.1). 

The key intermediate in these transformations was the hydrazide 83 obtained from the ester 82 by simple treatment with hydrazine hydrate. This intermediate was then transformed by aldehydes, sulfonic chlorides, and isothiocyanates to obtain various aryl hydrazones 84, sulfonylhydrazines 85, and thiocarbazides 86. 

Sulfonic acid anchoring groups, 8 683t Sulfonic acid catalysts, 10 477 Sulfonic acid hydrazides, 13 575, 593 Sulfonic acid-modified supported catalyst supports, 5 330-331 Sulfonic acids, 20 468... 

SOME UNUSUAL SULFINYL DERIVATIVES AND THEIR BEHAVIOR Reaction of a number of the nucleophiles in Table 6 with a sulfinyl sulfone (139) leads to substitution products ArS(0)Nu that are known from other studies to exhibit interesting and unusual chemical behavior of their own. These same sulfinyl derivatives can also be generated by reaction of the nucleophile with a sulfinyl chloride (142). Let us now discuss what is known about such compounds as sulfinyl azides, ArS(0)N3, sulfinyl hydrazides, ArS(0)NHNH2, etc. 

Oxidation of a thiomethyl group in indolo azepines to a sulfoxide and a sulfone has been reported (2004AP486). Thione 415 with a variety of hydrazides 416 under thermal conditions (n-butanol, reflux) gives fused triazoles 417 in moderate to good yields as the products of a substitution/cyclization sequence (Scheme 87, Section 5.2.1.3 (1993LA1141)). 

Reaction of isatin 3-monooxime sulfonate 159 with hydrazides leads to 1-aryltriazoli-nones 160 with 41-46% yields (equation 70) . Interaction of oxime PhC(=NHPh)CCl=... 

The product hydrazide may be sulfonated and decomposed by heating with a base in ethylene glycol to yield benzaldehyde, CeHsCHO. Many aromatic aldehydes may be produced by similar routes. The hydrazone derivative of toluenesulfonic acid reacts with an aldehyde or a ketone in the presence of a base catalyst, such as sodium ethoxide, to yield the corresponding olefin (Bamford-Stevens reaction) ... 

Addition of a nucleophile to the C-6 position of cytosine often results in fascile displacement reactions occurring at the N4 location. With hydroxylamine attack, nucleophilic displacement causes the formation of an N4-hydroxy derivative. A particularly important reaction for bioconjugate chemistry, however, is that of nucleophilic bisulfite addition to the C-6 position. Sulfonation of cytosine can lead to two distinct reaction products. At acid pH wherein the N-3 nitrogen is protonated, bisulfite reaction results in the 6-sulfonate product followed by spontaneous hydrolysis. Raising the pH to alkaline conditions causes effective formation of uracil. If bisulfite addition is done in the presence of a nucleophile, such as a primary amine or hydrazide compound, then transamination at the N4 position can take place instead of hydrolysis (Fig. 38). This is an important mechanism for adding spacer arm functionalities and other small molecules to cytosine-containing oligonucleotides (see Chapter 17, Section 2.1). 

---