using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	
	public static void Main()
	{
		var text = "a > b and b = 0 and (f = 1 and (g = 2 and j = 68) and v = 566) and a > b and b = 0 and (f = 1 and g = 2)";
		var pattern = @"(?x)
\s*\band\b\s* # whole word and enclosed with 0+ whitespaces
(?=           # start of a positive lookahead:   
  (?: 
    [^()]*    # 0 or more chars other than ( and )
    \((?>[^()]+|(?<o>\()|(?<-o>\)))*(?(o)(?!))\)  # a (...) substring with nested parens support
  )*          # repeat the sequence of above two patterns 0 or more times
  [^()]*$     # 0 or more chars other than ( and ) and end of string  
)             # end of the positive lookahead";
		var results = Regex.Split(text, pattern);
        foreach (var s in results)
        	Console.WriteLine(s);
	}
}