Reaction cone

Chloral added with stirring to a suspension of 3-morpholino-l-phenyl-2-buten-1-one in benzene, and the homogeneous soln. formed by an exothermic reaction coned. 1-0X0-1-phenyl-3-morpholino-5-hydroxy-6,6,6-tridilorohex-2-ene. Y ... 

The most widely used reactions are those of electrophilic substitution, and under controlled conditions a maximum of three substituting groups, e.g. -NO2 (in the 1,3,5 positions) can be introduced by a nitric acid/sul-phuric acid mixture. Hot cone, sulphuric acid gives sulphonalion whilst halogens and a Lewis acid catalyst allow, e.g., chlorination or brom-ination. Other methods are required for introducing fluorine and iodine atoms. Benzene undergoes the Friedel-Crafts reaction. ... 

Place 2 1 ml. (measured from a micro-burette) of nitro-benzene and 5 g. of granulated tin in a 150 ml. round-bottomed flask fitted with a small reflux water-condenser. (A large flask is employed because the mixture when subsequently boiled may bump violently.) Pour 10 ml. of cone. HCl down the condenser on this scale the reaction is not sufficiently vigorous to get out of control. Heat over a gauze for 15 minutes. Cool the flask and add a solution of 7 5 8- of NaOH in 10 ml. of water to redissolve the initial precipitate. Add about... 

Undergoes Cannizzaro s reaction, giving benzyl alcohol and benzoic acid (p. 229). Warm gently for several minutes, cool, add a few ml. of water and then cone. HCl, and cool again. Crystals of benzoic acid separate out on scratching the sides of the tube with a glass rod. 

Place a small quantity (t.e., about o-i g.) of the following substances (finely powdered) in a clean dry test-tube and add about I ml. of cone. H2SO4. Note any reaction in the cold, and then warm gently. Note any effervescence and any pronounced blackening (as distinct from mere darkening in colour). 

I. Action of sulphuric add. To 0 5 ml. of the alcohol, add 0 5 ml. of cone. H2SO4 and shake the mixture. Heat is evolved and a white gelatinous polymer gradually separates. The reaction is hastened by warming and the product darkens. 

Phthalein reaction. Place in a dry test-tube about 0 2 g. of the phenol and an equal quantity of phthalic anhydride (or acid), moisten with 2 drops (not more) of cone. H2SO4 and gently fuse together for about 1 minute. Allow to cool somewhat, and then add 10% NaOH solution in excess. 

Ltebermann Reaction To 1 minute crystal of sodium nitrite in a clean dry test-tube add 0 5 g. of phenol and heat very gently for about 20 seconds allow to cool and add twice the volume of cone. H2S04. On rotating the tube slowly in order to mix the contents, a deep green or deep blue coloration develops (some times only after i 2 minutes). Dilute cautiously with water the solution turns red. Now add an excess of NaOH solution the green or blue coloration reappears. 

Action of sodium hydroxide. Does not undergo the Cannizzaro reaction. It dissolves in dil. NaOH solution, giving a yellow solution from which the aldehyde is precipitated unchanged on acidification. If heated with cone. NaOH solution, salicylaldehyde slowly undergoes atmospheric oxidation to salicylic acid. 

Sulphuric add test. To 0-5 g. of oxalic acid or of an oxalate, add I ml. of cone. H2SO4 and warm CO and COg are evolved (cf. formic acid). The CO burns with a blue flame. Detect the COg by passing the mixed gases evolved into lime-water. It is essential to test for the COj in a separate reaction, or (if the same test-tube is used) before testing for CO. 

Phthalein reaction. Fuse together carefully in a dry test-tube a few crystals of phthalic acid or of a phthalate and an equal quantity of ph tol moistened with 2 drops of cone. H2SO4. Cool, dissolve in water and add NaOH solution in excess the bright red colour of phenolphthalein in alkaline solution is produced. 

Fluorescein reaction. Fuse together in a dry test-tube o-i g. of succinimide, O l g. of resorcinol and 2 drops of cone. HjSOi, Cool, add water and then NaOH solution in excess. A green fluorescent solution is obtained. 

Isocyanide reaction. Add a few drops of chloroform to about 0 2 g. of the substance, and then 2 3 ml. of ethanolic NaOH solution. Mix well and warm gently the foul odour of isocyanide (carbylamine) is produced. Immediately the odour of isocyanide is detected, cool the tube and add carefully an excess of cone. HCl the isocyanide is thus hydrolysed to the odourless amine. 

Phosphites, such as triisopropyl and triphenyl phosphite, are weaker electron donors than the corresponding phosphines, but they are used in some reactions because of their greater rr-accepting ability. The cyclic phosphite trimethylol-propane phosphite (TMPP) or 4-ethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]oc-tane (8), which has a small cone angle and small steric hindrance, shows high catalytic activity in some reactions It is not commercially available, but can be prepared easily[27]. 

The oxidation of 3-substituted indole to oxindoles can also be done with a mixture of DMSO and cone, hydrochloric acid[6-9]. This reaction probably involves a mechanism similar to the halogenation with a protonated DMSO molecule serving as the electrophile[10]. 

A solution of l,3-dimethyl-5-methoxyindole (4.5 g, 0.026 mol) in DMSO (27 ml) was maintained at as cone. HCl (23 ml, 0.77 mol) was added dropwise over 15 min. Stirring was continued for 3 h at room temperature and the reaction mixture was then poured into ice-watcr (100 ml). The mixture was neutralized vvith NaHCOj to pH 7 and extracted with EtOAc (100 ml x 2). The EtOAc was removed in vacuo and the residue purified by chromatography on silica using hexane-EtOAc (7 3) for elution. The yield was 4.35 g (88%). 

A number of chemiluminescent reactions have been studied by producing key reactants through pulsed electric discharge, by microwave dissociation, or by observing the reactions of atoms and free radicals produced in the inner cone of a laminar flame as they diffuse into the flame s cool outer cone (182,183). These are either combination reactions or atom-transfer reactions involving transfer of chlorine (184) or oxygen atoms (181,185—187), the latter giving excited oxides. 

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