ADB-INACA: Structural Characterization and Analytical Profile of a Primary Amide Indazole-3-Carboxamide Synthetic Cannabinoid

ADB-INACA (N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1H-indazole-3-carboxamide) is a synthetic cannabinoid belonging to the indazole-3-carboxamide class. Unlike its methyl ester analog MDMB-INACA, ADB-INACA features a primary amide (ADB) tail — a structural distinction that significantly influences its metabolic stability and receptor binding profile. This compound serves as a key reference standard in forensic cannabinoid analysis.

Molecular Identity

ParameterValue
Common NameADB-INACA
IUPAC NameN-(1-Amino-3,3-dimethyl-1-oxobutan-2-yl)-1H-indazole-3-carboxamide
Molecular FormulaC₁₄H₁₈N₄O₂
Molecular Weight274.32 g/mol
InChI KeyUFECWXZSRFBSHC-UHFFFAOYSA-N
SMILESNC(=O)C(C(C)(C)C)NC(=O)c1n[nH]c2c1cccc2
PubChem CID147306780

Structural Overview

ADB-INACA’s molecular architecture comprises three essential components: (1) a 1H-indazole core providing planar π-stacking for receptor interaction, (2) a 3-position carboxamide linker acting as a hydrogen-bonding motif, and (3) an ADB primary amide tail (1-amino-3,3-dimethyl-1-oxobutan-2-yl) with a bulky tert-butyl group and terminal CONH₂ replacing the methyl ester found in MDMB analogs.

ADB vs. MDMB: Structural Comparison

The ADB tail (primary amide, CONH₂) differs fundamentally from the MDMB tail (methyl ester, CO₂Me). This results in lower lipophilicity (logP ~1.9 vs. ~2.8), three hydrogen bond donors vs. two, and resistance to esterase-mediated hydrolysis. These differences affect blood-brain barrier permeability and metabolic clearance pathways.

Synthetic Route

The synthesis follows standard indazole-3-carboxamide coupling: 1H-indazole-3-carboxylic acid (CAS 4498-67-3) is activated with CDI or HATU, then coupled with 2-amino-3,3-dimethylbutanamide hydrochloride under basic conditions (DIPEA, DCM, 0°C to rt). Typical yields range from 70-85% after column chromatography.

Analytical Data

¹H NMR (400 MHz, DMSO-d₆): δ 13.65 (br s, 1H, indazole N-H), 8.45 (d, 1H, amide N-H), 8.12 (d, 1H, Ar-H), 7.68 (d, 1H, Ar-H), 7.48 (t, 1H, Ar-H), 7.32-7.28 (m, 2H, CONH₂), 4.48 (d, 1H, CH-CONH₂), 1.04 (s, 9H, C(CH₃)₃).

ESI-MS: [M+H]⁺ m/z 275.2 | HPLC Purity: ≥ 98%

References

  • Aipsin, Issue 34, Oct 2022: I-257
  • Aipsin, Issue 32, Aug 2022: XII-56
  • Aipsin, Issue 47, Nov 2023: VII-269
  • Forensic Science Education — NMS Labs Report
  • PubChem CID 147306780

Supply Information

Sun Pharma Chemical offers research-grade indazole-3-carboxylic acid (CAS 4498-67-3) and related indazole derivatives.

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