The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Anomalies in the reduction of 2,2′-diacetylbiphenyl》. Authors are Hall, D. Muriel; Ladbury, Joan E.; Lesslie, Mary S.; Turner, E. E..The article about the compound:Isoquinolin-6-olcas:7651-82-3,SMILESS:OC1=CC2=C(C=NC=C2)C=C1).COA of Formula: C9H7NO. Through the article, more information about this compound (cas:7651-82-3) is conveyed.
2,2′-Diacetylbiphenyl (I) formed 9,10-dimethylphenanthrene (II) on Clemmensen reduction. With LiAlH4 I gave 2 diastereoisomeric 2,2′-di(1-hydroxyethyl)biphenyls, (III) and (IV). III and IV reacted normally with HBr and, by the action of refluxing quinoline (V) on the resulting mixture of isomerides, 2,2′-divinylbiphenyl (VI) was prepared Reduction of I under Huang-Minlon conditions gave 2-methyl-3,4,5,6-dibenzocyclohepta-1,3,5-triene (VII). 2,2′-Di-(1-hydroxy-1-methylethyl)biphenyl (VIII) was dehydrated in 3 ways, to give 2,7,7-trimethyl-3,4,5,6-dibenzocyclohepta-1,3,5-triene (IX), 2,2′-diisopropenylbiphenyl (X), or 2,7-dihydro-2,2,7,7-tetramethyl-3,4,5,6-dibenzoxepin (XI). It had been thought that the Clemmensen reduction of I may possibly serve as a route to 2,2′-diethylbiphenyl (XII), but the above results indicated that XII could not be prepared by this method. Finely ground phenanthraquinone (84 g.) was added to MeMgI from 39 g. Mg and MeI and after addition of 500 cc. C6H6 the mixture was refluxed 2 hrs. and 6.5 g. of starting material was recovered by use of NaHSO3. The Et2-C6H6 washed with brine, distilled to a volume of 300 cc. and cooled gave 75 g. 9,10-dihydro-9,10-dihydroxy-9,10-dimethylphenanthrene (XIII), m. 163-4°. The use of 6 moles MeMgI did not improve the yield of XIII and greatly extended the time of operation. XIII (38 g.) in 380 cc. AcOH treated at 70° during 10 min. with 16 g. CrO3 in 160 cc. H2O, the mixture left 10 min. at 70°, and the crude product purified gave 89% I, m. 93-4° (from cyclohexane). I and 4 moles of MeMgI gave 80% VIII, b. 320°, m. 139-40° (from alc.). I (28 g.) and HCl refluxed 6 hrs. in the presence of Zn-Hg gave 24.5 g. (crude) II, m. 144°; picrate, m. 192-3°. The material was identical with a specimen of authentic II. I (11.9 g.) heated 1 hr. with LiAlH4 in Et2O and the solid repeatedly recrystallized from C6H6 gave III as prisms, m. 147.5-9.0°, and IV as long prisms, m. 153-5°. III (1 g.) heated 2.5 hrs. with 15 cc. 20% H2SO4 gave 2,7-dihydro-2,7-dimethyl-3,4,5,6-dibenzoxepin (XIV), m. 77-80° (from MeOH). IV similarly treated but with 7 hrs. heating gave XIV, m. 74-8°. Thus the product seemed to be a mixture III gave XIV as the main product but IV more obviously gave a mixture Either III or IV or a mixture of both heated 15 min. with a large excess of HBr gave about 20% 2,2′-di(1-bromoethyl)biphenyl (XV), m. 88-92°. Second crop m. 71-9°. These also gave VI when dehydrobrominated with V. A solution of XV in V refluxed 5 min. gave VI, m. 80-1°. The m.p. remained unchanged after several months. Hydrogenation in alc. solution with PtO2 and H gave XII, b13.5 139-40°, nD25 1.5626. XII(21 g.), 35.6 g. (2 moles) N-bromosuccinimide, and 0.1 g. Bz2O2 in dry CCl4 refluxed 3 hrs. yielded 25.5 g. (crude) XV, m. 87-90°. I(20 g.), 34 g. NaOH, 34 cc. 85% aqueous H2NNH2, and 500 cc. triethylene glycol refluxed 2 hrs., H2O and excess H2NNH2.H2O removed until the temperature reached 195°, then refluxed 4 hrs., and the residual product distilled gave 10 g. pure VII, m. 49.5-50.5°. The residue treated with picric acid yielded 0.5 g. II picrate. VII (7.5 g.)in AcOH shaken with H and Pd yielded 2-methyl-3,4,5,6-dibenzocyclohepta-3,5-diene (XVI) as an oil, b1 120°, nD25 1.6102. Proof of structure of XVI was confirmed by the ultraviolet absorption spectrum. Further proof for the structure of VII came from its behavior on oxidation. VII (0.513 g.) in 2.5 cc. xylene refluxed 5.5 hrs. with 0.304 g. SeO2 and the residue treated with 2,4-dinitrophenylhydrazine gave 2-methyl-7-oxo-3,4,5,6-dibenzocyclohepta-1,3,5-triene 2,4-dinitrophenylhydrazone, m. 252° (decomposition) (from C6H6-ligroine). VII (1.6 g.) in AcOH heated 1.75 hrs. with 7 g. Na2Cr2O7 in AcOH yielded phenanthraquinone (XVII), m. 208-9°; quinoxaline derivative (with o-phenylenediamine), m. 222-3°. Chromatography of the residual product on Al2O3 gave 2-acetyl-2′-formylbiphenyl (XVIII). The Na2CO3 washings acidified gave a gum which solidified to 2′-acetylbiphenyl-2-carboxylic acid, m. 120-1° (from alc. and cyclohexane). VI (1 g.) in AcOH similarly oxidized with Na2Cr2O7 in AcOH gave XVII. This was a test for the bridged biphenyl system. I (5 g.) and 2.5 cc. 85% H2NNH2.H2O in alc. kept at 60-40° overnight gave 0.2 g. II; addition of NH3 to the filtrate precipitated 2.6 g. 3,8-dimethyl-4,5,6,7-dibenzo-1,2-diazocine (XIX), prisms, m. 167-8° (from aqueous alc.). In other preparations the solution was refluxed for several hrs. to give more II and less XIX. XIX (0.3 g.) and 15 cc. dilute H2SO4 refluxed 1 hr. gave I, m. 91-3°. XIX (0.6 g.) heated 3.5 hrs. at 195° with 0.7 g. NaOH and 11 cc. triethylene glycol yielded 0.5 g. crude II, which was purified from alc. XIX remained unaffected by hot aqueous-alc. H2NNH2.H2O or NaOH or when heated above its m.p. alone or with Cu bronze. Meerwein-Ponndorf-Verley reduction of I was attempted but the product was a mixture and no pure compounds could be isolated. VIII (2 g.) refluxed 1 hr. with 60 cc. 4N H2SO4 gave XI, m. 92-3° (from MeOH). A mixture of 10 g. VIII and 0.1 g. naphthalene-2-sulfonic acid heated 15 min. at 140° gave IX, m. 100-1°. A suspension of IX or of XI in HBr refluxed 1 hr. gave IX. IX (10 g.) in AcOH-EtOAc shaken with H in the presence of PtO2 for several hrs. yielded 9.5 g. 2,2,7-trimethyl-3,4,5,6-dibenzocyclohepta-3,5-diene, prisms, m. 67-71° (from alc.). IX (5 g.) refluxed at 320° with a little Cu bronze and activated Al2O3 and the b.p. dropped within 10 min. to 295° gave 3 g. X, b5 136°, nD21 1.5890. A small amount of XI was also isolated. An AcOH solution of X was shaken 1 hr. with H and PtO2 to give 2,2′-diisopropylbiphenyl. X (1.3 g.) refluxed 1.5 hrs. with 20 cc. HBr gave IX. X (1 g.) refluxed 5 hrs. with 50% H2SO4 yielded 0.5 g. IX. VI (0.5 g.) and HBr refluxed 1.5 hrs. gave XV. IX (1.1 g.) in AcOH and 5.6 g. Na2Cr2O7 heated 1.75 hrs. and the residue treated with o-phenylenediamine gave the quinoxaline derivative of XVII. The ligroine extract yielded XVIII, m. 84°. Dinitrophenylhydrazone formation was accompanied by cyclization; 7-oxo-3,4,5,6-dibenzocyclohepta-1,3,5-triene 2,4-dinitrophenylhydrazone, m. about 208° (decomposition), was isolated. The Na2CO3 washings were acidified to give a gum from which 2 impure crystallization acids were isolated. Quantities were too small for further investigation.
Compound(7651-82-3)COA of Formula: C9H7NO received a lot of attention, and I have introduced some compounds in other articles, similar to this compound(Isoquinolin-6-ol), if you are interested, you can check out my other related articles.
Reference:
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method