Sodium Iodide → 1,3-Naphthalenediamine
Reaction equation
[N+:1]([C:4]1[CH:13]=[C:12]([N+:14]([O-])=O)[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[C:5]=1O)([O-])=O.[I-].[Na+].[I-]>>[NH2:14][C:12]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[CH:5]=[C:4]([NH2:1])[CH:13]=1Participants
Procedure
In Scheme 1, conversion of 2,4-dinitro-1-hydroxynaphthalene (Martius Yellow; 1) to the iodide (3) is carried out by conversion to the trifluorosulfonate 2, followed by reaction with NaI. Concomitant reduction of the two nitro groups and removal of the iodine from 3 with SnCl2 then gave the 1,3-diaminonaphthalene 4. Protection of the amines with BOC anhydride, followed by electrophilic iodination with NIS (general method of Boger et al., J. Org. Chem., 2001 66, 5163), gave iodide 5. Allylation of the carbamate (NaH/allyl bromide) to give 6, followed by a Bu3SaH promoted 5-exo-trig free-radical cyclization of this with in situ TEMPO (general method of Boger et al.; J. Org. Chem., 2001, 66, 5163) gave 7, which was subsequently reduced (Zn/AcOH) to the alcohol 8 in quantitative yield. The alcohol was converted to the chloride 9 with Ph3P/CCl4. Acid-catalyzed deprotection (TFA) of 9 followed by regioselective coupling with 4-methoxysuccinic acid using EDCI gave the required 10a. This was deblocked by a suitable reagent, (for example, Grubb's carbene [Alcaide et al., Org. Lett., 2001, 3623] or preferably, sodium phenylsulfonate/camphorsulfonic acid/Pd(Ph3P)4 (modification of the method of Honda et al., J. Org. Chem. 1997, 62 8932) to the required 11a. This provides a 10-step synthesis of 11a from 1, with an overall yield of 32%. A similar synthesis gave the analogue 11b in 19% overall yield.
Workup
- customConcomitant reduction of the two nitro groups and removal of the iodine from 3 with SnCl2
Sources & evidence
- ORD record
- ord-bbf51c087ce649728cd6acce0ffa6d76
- Source dataset
- uspto-grants-2007_06
- Patent number
- US07235578B2
Reaction notes
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