string projectFileName = @"C:DownloadsToBeBuiltToBeBuiltToBeBuilt.csproj";

ProjectCollection pc = new ProjectCollection();
pc.SetGlobalProperty("Configuration", "Debug");
pc.SetGlobalProperty("Platform", "x86");
pc.SetGlobalProperty("OutDir", @"C:DownloadsArtifacts");

Dictionary<string, string> globalProperty = new Dictionary<string, string>();
globalProperty.Add("Configuration", "Debug");
globalProperty.Add("Platform", "x86");
globalProperty.Add("OutDir", @"C:DownloadsArtifacts");

BuildRequestData BuidlRequest = new BuildRequestData(projectFileName, globalProperty, "15.0", new string[] { "Build" }, null);
BuildResult buildResult = BuildManager.DefaultBuildManager.Build(new BuildParameters(pc), BuidlRequest);
BuildResultCode a = buildResult.OverallResult;

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props')" />
  ...
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>binx86Debug</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <DebugType>full</DebugType>
    <PlatformTarget>x86</PlatformTarget>
    <ErrorReport>prompt</ErrorReport>
    ...
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data.DataSetExtensions" />
    <Reference Include="Microsoft.CSharp" />
    <Reference Include="System.Data" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Program.cs" />
    <Compile Include="PropertiesAssemblyInfo.cs" />
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)Microsoft.CSharp.targets" />
  <Target Name="Build">
    <Csc Sources="@(Compile)"/>
  </Target>
</Project>