Regular Expressions for validating SMILES, InChi, InChiKey

_smiles_inchi_annotated.js

//SMILES, Inchi Regex , by lo sauer - lsauer.com
//Here's a PREG version for SMILES validation (JavaScript) beyond a length of 5:
var x = "OC[C@@H](O1)[C@@H](O)[C@H](O)[C@@H]2[C@@H]1c3c(O)c(OC)c(O)cc3C(=O)O2"

x.trim().match(/^([^J][a-z0-9@+\-\[\]\(\)\\\/%=#$]{6,})$/ig)[0]
>"OC[C@@H](O1)[C@@H](O)[C@H](O)[C@@H]2[C@@H]1c3c(O)c(OC)c(O)cc3C(=O)O2"

//for the most frequent organic molecules
x.trim().match(/^([^J][0-9BCOHNSOPrIFla@+\-\[\]\(\)\\\/%=#$]{6,})$/ig)

//generic Perl RegEx:
/^([^J][A-Za-z0-9@+\-\[\]\(\)\\\/%=#$]+)$/

//Note: The only letter not appearing on the Periodic Table is the letter "J"
//Annotated
x.trim().match(/^([^J][0-9BCOHNSOPrIFla@+\-\[\]\(\)\\\/%=#$]{6,})$/ig)

//if you need a carbon count:
x.toLowerCase().split('').map(function(v,k){return +'c'==v;})
>[false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false,
  false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, 
  false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, 
  false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, 
  false, false, false, false]
x.toLowerCase().split('').map(function(v,k){return 'c'==v|0;})
>[0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1,
  0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0]
if(!Array.prototype.hasOwnProperty('sum'))
{
    function (){return this.reduce(function(a,b){return a+b})}
}

x.toLowerCase().split('').map(function(v,k){return 'c'==v|0;}).sum()
>14

Array.prototype.atomCount = function(t){ return this.map(function(v,k){return t==v|0;}).reduce(function(a,b){return a+b}) };

InChi.js

// International Chemical Identifier Regex, by lo sauer - lsauer.com
// Morphine InchI:
var x="InChI=1S/C17H19NO3/c1-18-7-6-17-10-3-5-13(20)16(17)21-15-12(19)4-2-9(14(15)17)8-11(10)18/h2-5,10-11,13,16,19-20H,6-8H2,1H3/t10-,11+,13-,16-,17-/m0/s1"

// applying an organic character-subset
// we could check for the length property, but in case of 0 matches 'null' is returned -> hence !!.. \ generally equal to Boolean(..) 
!!x.trim().match(/^((InChI=)?[^J][0-9BCOHNSOPrIFla+\-\(\)\\\/,pqbtmsih]{6,})$/ig)
>true
//generic:
x.trim().match(/^((InChI=)?[^J][0-9a-z+\-\(\)\\\/,]+)$/ig)
>true

InChiKey.js

// International Chemical Identifier KEY Regex, by lo sauer - lsauer.com
// The InChIKey, or hashed InChI, is a fixed length (25 character) condensed digital representation 
// of the InChI, which tries to be unique but is not human-comprehensible. It uses a BASE26  alphabet (Hexavigesimal)!
// The last character of an InChIKey is computed from the rest of the InChIKey 
// The InChIKey specification facilitates web searches for chemical compounds, owing to unqiue referencing 
// of compounds with a concise key, which is problematic with the full-length InChI (e.g. GET url limit is 1600 chars)

// From the official documents ( http://chemdata.nist.gov/InChI/inchi-hash.pdf ):
	// "The InChIKey is a character signature based on a hash code of the InChI string. Also, this hash
	 // may serve as a checksum for verifying InChI, for example, after transmission over a network."
	 
	 // InChIKey has four (4) distinct components: a 14-character hash of the basic (Mobile-H)
	// InChI layer (without /p segment accounting for added or removed protons); a 8-character
	// hash of the remaining layers; a 1 character is a flag indicating selected features (e.g.
	// presence of fixed-H layer); a 1 character is a “check” character. The overall length of
	// InChIKey is fixed at 25 characters, including separator:
	// AAAAAAAAAAAAAA-BBBBBBBBCD

	// This is significantly shorter than a typical InChI string (for example, the average length
	// of InChI string for Pubchem collection is 146 characters).
	// --------------------------------
	// InChIKey layout is as follows:
	// --------------------------------
	// AAAAAAAAAAAAAA
	// First block (14 letters)
	// Encodes molecular skeleton (connectivity)
	// BBBBBBBB
	// Second block (8 letters)
	// Encodes proton positions (tautomers), stereochemistry, isotopomers, reconnected layer
	// C
	// Flag character
	// Indicates InChI version, presence of a fixed-H layer, isotopes, and stereochemical
	// information.
	// D
	// Check character, obtained from all symbols except delimiters, i.e. from
	// AAAAAAAAAAAAAABBBBBBBBC

	// All symbols except the delimiter (a dash, that is, a minus) are uppercase English letters
	// representing a “base-26” encoding.
// see also:http://en.wikipedia.org/wiki/Hexavigesimal

//InChiKey v1.2 length: 14-10-1
//InChIKey v1.2 for morphine is BQJCRHHNABKAKU-KBQPJGBKSA-N
var x = 'BQJCRHHNABKAKU-KBQPJGBKSA-N'
25===x.length && '-'===x[14]
&& !!x.match(/^([0-9A-Z\-]+)$/)
>false
//enzyme ligand Copper - InchiKey: RYGMFSIKBFXOCR-UHFFFAOYSA-N
var x = 'RYGMFSIKBFXOCR-UHFFFAOYSA-N'
27===x.length && '-'===x[14] && '-'===x[25]
&& !!x.match(/^([0-9A-Z\-]+)$/)
>true

smiles_inchi_annotated.js

// Simplified Molecular Input Line Entry Specification (SMILES) Regex annotated, by lo sauer - lsauer.com
/^(    //starting with
[^J]   //must not contain J, which is the only letter absent from the periodic table
[0-9   // number for cyclic connection quantifiers and charge; e.g. [Co+3] or [Co+++]
BCOHNSOPrIFla  //"organic subset": B, C, N, O, P, S, F, Cl, Br, I -> do not require [] in SMILES; additionally: Na, Cl, Fl 
@      // Stereocenter configuration descriptor, usually tetrahedral carbon e.g. L-Ala N[C@@H](C)C(=O)O vs. D-Ala N[C@H](C)C(=O)O
%      // unique labels: C14 is a carbon hold the ring closure labels 1 and 2; C%12 holds the unique label 12
+\-    // +- the charge sign
\[\]   // [] is used to delinate atoms e.g. [Co+++]
\(\)   // () branching-descriptors of the sparse-tree (rings are broken in SMILES), e.g. CCC(=O)O for propionic acid 
\\\/   // /\ for configuration around double bonds e.g. F/C=C/F... trans-difluoroethene,  
=      // double bonds e.g. O=C=O (carbon dioxide)
#      // triple bonds e.g. C#N (hydrogen cyanide,)
$      // quadruple bonds e.g.  [Ga-]$[As+] (gallium arsenide)
]{6,}  // length must be > 5
)$
/ig   //ending with, search global, case-insensitive

/**
 * SMARTS
*/
// SMARTS...Smiles arbitrary target specification has commas in addition to the SMILES character-set
// bonds are defined as:  '-' (single), '=' (double), '#' (triple), ':' (aromatic) and '~' (any)
// logic operators: 
//       OR operator ',' 
//       AND operator '&' (lower priority ';')
//       NOT operator  '!'
// more information: http://en.wikipedia.org/wiki/Smiles_arbitrary_target_specification

//REGEX
/^([^J][0-9BCOHNSOPrIFla@+\-\[\]\(\)\\\/%=#$,.~&!]{6,})$/


//examples 
// definitions of hydrogen bond donors and acceptors used to apply Lipinski's Rule of Five:
var x="[N,n,O;!H0]"
var y="[#7,#8;!H0]"

!!x.trim().match(/^([^J][0-9BCOHNSOPrIFla@+\-\[\]\(\)\\\/%=#$,.~;&!]{6,})$/ig)
>true
y.trim().match(/^([^J][0-9BCOHNSOPrIFla@+\-\[\]\(\)\\\/%=#$,.~;&!]{6,})$/ig)
>true
// definition of aliphatic amines, likely to protonate at physiological pH:
var x="[$([NH2][CX4]),$([NH]([CX4])[CX4]),$[NX3]([CX4])([CX4])[CX4])]"
>true