PMID- 35956765
OWN - NLM
STAT- MEDLINE
DCOM- 20220815
LR  - 20230916
IS  - 1420-3049 (Electronic)
IS  - 1420-3049 (Linking)
VI  - 27
IP  - 15
DP  - 2022 Jul 27
TI  - A Straightforward Access to New Amides of the Melanin Precursor 
      5,6-Dihydroxyindole-2-carboxylic Acid and Characterization of the Properties of 
      the Pigments Thereof.
LID - 10.3390/molecules27154816 [doi]
LID - 4816
AB  - We report herein an optimized procedure for preparation of carboxamides of 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA), the main biosynthetic precursor of 
      the skin photoprotective agents melanins, to get access to pigments with more 
      favorable solubility properties with respect to the natural ones. The developed 
      procedure was based on the use of a coupling agent (HATU/DIPEA) and required 
      protection of the catechol function by easily removable acetyl groups. The 
      O-acetylated compounds could be safely stored and taken to the reactive 
      o-diphenol form just before use. Satisfactorily high yields (>85%) were obtained 
      for all amides. The oxidative polymerization of the synthesized amides carried 
      out in air in aqueous buffer at pH 9 afforded melanin-like pigmented materials 
      that showed chromophores resembling those of DHICA-derived pigments, with a good 
      covering of the UVA and the visible region, and additionally exhibited a good 
      solubility in alcoholic solvents, a feature of great interest for the 
      exploitation of these materials as ingredients of dermocosmetic formulations.
FAU - Argenziano, Rita
AU  - Argenziano R
AD  - Department of Chemical Sciences, University of Naples "Federico II", Via Cintia 
      21, I-80126 Naples, Italy.
FAU - Della Greca, Marina
AU  - Della Greca M
AUID- ORCID: 0000-0001-6530-605X
AD  - Department of Chemical Sciences, University of Naples "Federico II", Via Cintia 
      21, I-80126 Naples, Italy.
FAU - Panzella, Lucia
AU  - Panzella L
AUID- ORCID: 0000-0002-2662-8205
AD  - Department of Chemical Sciences, University of Naples "Federico II", Via Cintia 
      21, I-80126 Naples, Italy.
FAU - Napolitano, Alessandra
AU  - Napolitano A
AUID- ORCID: 0000-0003-0507-5370
AD  - Department of Chemical Sciences, University of Naples "Federico II", Via Cintia 
      21, I-80126 Naples, Italy.
LA  - eng
GR  - PRIN 2017 2017YJMPZN/MIUR/
PT  - Journal Article
DEP - 20220727
PL  - Switzerland
TA  - Molecules
JT  - Molecules (Basel, Switzerland)
JID - 100964009
RN  - 0 (Amides)
RN  - 0 (Carboxylic Acids)
RN  - 0 (Indoles)
RN  - 0 (Melanins)
RN  - 0 (melanin precursors)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
SB  - IM
MH  - Amides
MH  - *Carboxylic Acids
MH  - Indoles
MH  - *Melanins/chemistry
PMC - PMC9369804
OTO - NOTNLM
OT  - DHICA amides
OT  - catechol
OT  - chromophores
OT  - dermocosmetic formulations
OT  - melanins
OT  - oxidative polymerization
OT  - pigments
COIS- The authors declare no conflict of interest.
EDAT- 2022/08/13 06:00
MHDA- 2022/08/16 06:00
PMCR- 2022/07/27
CRDT- 2022/08/12 01:19
PHST- 2022/06/28 00:00 [received]
PHST- 2022/07/18 00:00 [revised]
PHST- 2022/07/26 00:00 [accepted]
PHST- 2022/08/12 01:19 [entrez]
PHST- 2022/08/13 06:00 [pubmed]
PHST- 2022/08/16 06:00 [medline]
PHST- 2022/07/27 00:00 [pmc-release]
AID - molecules27154816 [pii]
AID - molecules-27-04816 [pii]
AID - 10.3390/molecules27154816 [doi]
PST - epublish
SO  - Molecules. 2022 Jul 27;27(15):4816. doi: 10.3390/molecules27154816.